A new analytical model for geometric size and forming force prediction in incremental flanging(IF)is presented in this work.The complex deformation characteristics of IF are considered in the modeling process,which ca...A new analytical model for geometric size and forming force prediction in incremental flanging(IF)is presented in this work.The complex deformation characteristics of IF are considered in the modeling process,which can accurately describe the strain and stress states in IF.Based on strain analysis,the model can predict the material thickness distribution and neck height after IF.By considering contact area,strain characteristics,material thickness changes,and friction,the model can predict specific moments and corresponding values of maximum axial forming force and maximum horizontal forming force during IF.In addition,an IF experiment involving different tool diameters,flanging diameters,and opening hole diameters is conducted.On the basis of the experimental strain paths,the strain characteristics of different deformation zones are studied,and the stable strain ratio is quantitatively described through two dimensionless parameters:relative tool diameter and relative hole diameter.Then,the changing of material thickness and forming force in IF,and the variation of minimum material thickness,neck height,maximum axial forming force,and maximum horizontal forming force with flanging parameters are studied,and the reliability of the analytical model is verified in this process.Finally,the influence of the horizontal forming force on the tool design and the fluctuation of the forming force are explained.展开更多
The northwestern margin of Junggar Basin is the region with the richest oil sand resources in China.For better understanding the enrichment rules and deployment of exploration and development of regional oil sand,it i...The northwestern margin of Junggar Basin is the region with the richest oil sand resources in China.For better understanding the enrichment rules and deployment of exploration and development of regional oil sand,it is of great scientific significance to study the accumulation conditions of oil sand in different strata and mining areas of the Junggar Basin.Through a large number of field investigations,drilling verification and sampling tests,it is found that the oil sand in the region covers an area of 2000 km^(2),with shallow and thick reservoir,and predicted resource of 180 million tons.The oil sand resources are mainly distributed in four geological strata,namely the Middle Triassic Karamay Formation,Early Jurassic Badaowan Formation,Late Jurassic Qigu Formation,and Early Cretaceous Qingshuihe Formation.The reservoir is mainly composed of sandstone with high porosity and permeability,and the reservoir space is mainly intergranular pores with a medium average oil content.The oil sand deposit in the region is a typical destructive oil reservoir.The crude oil in the oil sand layer is degraded and thickened from the deep to the shallow,the content of saturated hydrocarbon decreased,and the content of aromatic hydrocarbon,non-hydrocarbon and asphaltene increased.The oil source comes from the deep Permian hydrocarbon-generating depression.Unconformities,faults and marginal fan delta-braided river depositional systems constitute effective migration and storage systems.Caprocks of the Upper Triassic Baijiantan Formation,Lower Jurassic Sangonghe Formation and Lower Cretaceous Hutubihe Formation were formed by three large scale lake transgressions.The Indosinian,Yanshan and Late Yanshan movements are the main driving forces for the migration of deep oil and gas to the shallow edge to form oil sand deposits.It is considered that the oil sand in the northwestern margin of Junggar Basin is of a slope complex migration type.展开更多
The carcass layer is the innermost structure of flexible marine risers and is responsible for resisting external pressure.It has an“S”section with a spiral interlocking feature.After the multi-pass roll forming of a...The carcass layer is the innermost structure of flexible marine risers and is responsible for resisting external pressure.It has an“S”section with a spiral interlocking feature.After the multi-pass roll forming of a flat steel strip,a carcass layer is formed by lock forming.During roll forming,the steel strip undergoes significant plastic deformation,and its local area accumulates residual stress owing to multiple loading and unloading cycles.These phenomena complicate the design and analysis of the carcass layer multi-pass roll forming(CLMRF)process and cause issues in the carcass layer during manufacturing,such as strip fracture and low forming quality.Thus,herein,CLMRF was investigated to clarify the stress distribution,and a parameter analysis was performed.First,the CLMRF process was designed on the basis of classical roll-forming design theory.Second,a finite element model was established,and CLMRF was simulated.Third,the distributions of the forming stress and residual stress of the strip during CLMRF were investigated.Finally,the influences of the strip thickness,roll gap,roll distance,and angular increment were investigated.The conclusions of this study can be used to provide technical guidance in the manufacturing of flexible risers.展开更多
Spiral bevel gears are critical transmission components,and are widely used in the aerospace field.This paper proposes a new multi-DOF envelope forming process for fabricating spiral bevel gears.Firstly,the multi-DOF ...Spiral bevel gears are critical transmission components,and are widely used in the aerospace field.This paper proposes a new multi-DOF envelope forming process for fabricating spiral bevel gears.Firstly,the multi-DOF envelope forming principle of spiral bevel gears is proposed.Secondly,the design methods for the envelope tool geometry and movement are proposed based on the envelope geometry and movement relationships.Thirdly,the metal flow and tooth filling laws are revealed through 3D FE simulation of the multi-DOF envelope forming process of a typical spiral bevel gear.Fourthly,a new method for separating the envelope tool and the formed spiral bevel gear with back taper tooth is proposed to avoid their interference.Finally,experiments on multi-DOF envelope forming of this typical spiral bevel gear are conducted using new heavy load multi-DOF envelope forming equipment.The simulation and experimental results show the feasibility of the proposed multi-DOF envelope forming process for fabricating spiral bevel gears with back taper tooth and the corresponding process design methods.展开更多
The influence of geometric configuration on the friction characteristics during incremental sheet forming of AA5052 was analyzed by integrating surface morphology and its characteristic parameters,along with plastic s...The influence of geometric configuration on the friction characteristics during incremental sheet forming of AA5052 was analyzed by integrating surface morphology and its characteristic parameters,along with plastic strain,contact pressure,and area.The interface promotes lubrication and support when wall angles were≤40°,a 0.5 mm-thin sheet was used,and a 10 mm-large tool radius was employed.This mainly results in micro-plowing and plastic extrusion flow,leading to lower friction coefficient.However,when wall angles exceed 40°,significant plastic strain roughening occurs,leading to inadequate lubrication on the newly formed surface.Increased sheet thickness and decreased tool radius elevate contact pressure.These actions trigger micro-cutting and adhesion,potentially leading to localized scuffing and dimple tears,and higher friction coefficient.The friction mechanisms remain unaffected by the part’s plane curve features.As the forming process progresses,abrasive wear intensifies,and surface morphology evolves unfavorably for lubrication and friction reduction.展开更多
This article examines the influence of annealing temperature on fracture toughness and forming limit curves of dissimilar aluminum/silver sheets.In the cold roll bonding process,after brushing and acid washing,the pre...This article examines the influence of annealing temperature on fracture toughness and forming limit curves of dissimilar aluminum/silver sheets.In the cold roll bonding process,after brushing and acid washing,the prepared surfaces are placed on top of each other and by rolling with reduction more than 50%,the bonding between layers is established.In this research,the roll bonding process was done at room temperature,without the use of lubricants and with a 70%thickness reduction.Then,the final thickness of the Ag/Al bilayer sheet reached 350μm by several stages of cold rolling.Before cold rolling,it should be noted that to decrease the hardness created due to plastic deformation,the roll-bonded samples were subjected to annealing heat treatment at 400℃for 90 min.Thus,the final samples were annealed at 200,300 and 400℃for 90 min and cooled in a furnace to examine the annealing temperature effects.The uniaxial tensile and microhardness tests measured mechanical properties.Also,to investigate the fracture mechanism,the fractography of the cross-section was examined by scanning electron microscope(SEM).To evaluate the formability of Ag/Al bilayer sheets,forming limit curves were obtained experimentally through the Nakazima test.The resistance of composites to failure due to cracking was also investigated by fracture toughness.The results showed that annealing increases the elongation and formability of the Ag/Al bilayer sheet while reduces the ultimate tensile strength and fracture toughness.However,the changing trend is not the same at different temperatures,and according to the results,the most significant effect is obtained at 300℃and aluminum layers.It was also determined that by increasing annealing temperature,the fracture mechanism from shear ductile with small and shallow dimples becomes ductile with deep cavities.展开更多
To overcome the shortage of complex equipment,large volume,and high energy consumption in space capsule manufacturing,a novel sliding pressure Joule heat fuse additive manufacturing technique with reduced volume and l...To overcome the shortage of complex equipment,large volume,and high energy consumption in space capsule manufacturing,a novel sliding pressure Joule heat fuse additive manufacturing technique with reduced volume and low energy consumption was proposed.But the unreasonable process parameters may lead to the inferior consistency of the forming quality of single-channel multilayer in Joule heat additive manufacturing process,and it is difficult to reach the condition for forming thinwalled parts.Orthogonal experiments were designed to fabricate single-channel multilayer samples with varying numbers of layers,and their forming quality was evaluated.The influence of printing current,forming speed,and contact pressure on the forming quality of the single-channel multilayer was analyzed.The optimal process parameters were obtained and the quality characterization of the experiment results was conducted.Results show that the printing current has the most significant influence on the forming quality of the single-channel multilayer.Under the optimal process parameters,the forming section is well fused and the surface is continuously smooth.The surface roughness of a single-channel 3-layer sample is 0.16μm,and the average Vickers hardness of cross section fusion zone is 317 HV,which lays a foundation for the subsequent use of Joule heat additive manufacturing technique to form thinwall parts.展开更多
Short process forming techniques for brazing and soldering materials can shorten the process,improve product quality,and increase production efficiency,which has received much attention from welding researchers.This r...Short process forming techniques for brazing and soldering materials can shorten the process,improve product quality,and increase production efficiency,which has received much attention from welding researchers.This review mainly summarized the research reports on short process forming techniques for brazing and soldering materials.Firstly,the traditional process and its shortcomings were presented.Secondly,the latest research of short process forming technologies,such as continuous casting technique,atomization powder technique,solder ball forming technique,and rapid solidification technique,was summarized,and the traditional forming performance of several brazing and soldering materials was introduced.Finally,the current restrictions and research trends of short process forming technique for brazing and solder materials were put forward,providing theoretical guidance and reference for related research and technique development in brazing and soldering field.展开更多
An analytical model for contact area and contact stress considering the loading history in incremental sheet forming(ISF)was established.Then,by integrating with the directional characteristics of friction force and h...An analytical model for contact area and contact stress considering the loading history in incremental sheet forming(ISF)was established.Then,by integrating with the directional characteristics of friction force and horizontal force in the process,a friction test method reflecting the forming characteristics of ISF was proposed.Friction coefficients during the forming processes of parts with different wall angles were measured under various plane curves,process paths,and lubrication conditions.Furthermore,the accuracy of the analytical model,as well as the measured friction coefficients and their variation trends,was verified through comparative analysis with experimental results,simulation data,and outcomes from other existing models.The results indicate that the influence of the plane curve characteristics and process paths of parts on the friction condition is not significant.Under the lubrication conditions of L-HM46 oil,MoS_(2)grease,graphite powder,and dry friction,the friction coefficient shows a gradually increasing trend.Notably,when the wall angle is≤40°,the friction coefficient remains relatively constant;however,when the wall angle exceeds 40°,the friction coefficient increases progressively.展开更多
Four types of Mg-5Zn porous scaffolds with different pore geometries,including body-centered cubic(bcc),the rhombic dodecahedron(RD),gyroid(G),and primitive(P)types,were designed and fabricated using selective laser m...Four types of Mg-5Zn porous scaffolds with different pore geometries,including body-centered cubic(bcc),the rhombic dodecahedron(RD),gyroid(G),and primitive(P)types,were designed and fabricated using selective laser melting.Their forming quality,compression mechanical properties,and degradation behavior were investigated.Results indicate that the fabricated scaffolds exhibit good dimensional accuracy,and the surface chemical polishing treatment significantly improves the forming quality and reduces porosity error in porous scaffolds.Compared to the ones with rod structures(bcc,RD),the scaffolds with surface structures(G,P)have less powder particle adhesion.The G porous scaffold exhibits the best forming quality for the same design porosity.The predominant failure mode of scaffolds during compression is a 45°shear fracture.At a porosity of 75%,the compression property of all scaffolds meets the compressive property requirements of cancellous bone,while bcc and G structures show relatively better compression property.After immersion in Hank's solution for 168 h,the B-2-75% pore structure scaffold exhibits severe localized corrosion,with fractures in partial pillar connections.In contrast,the G-3-75% pore structure scaffold mainly undergoes uniform corrosion,maintaining structural integrity,and its corrosion rate and loss of compressive properties are less than those of the B-2-75%structure.After comparison,the G-pore structure scaffold is preferred.展开更多
Dear Editor,This letter investigates the grid-forming control for power converters.Recently,grid-forming control based on matching of synchronous machines was suggested by using continuous measurements.In the present ...Dear Editor,This letter investigates the grid-forming control for power converters.Recently,grid-forming control based on matching of synchronous machines was suggested by using continuous measurements.In the present letter,we suggest a digital implementation using artificial delays where the controller employs the discrete-time measurements only.展开更多
To improve braking performance and achieve lightweight in transport equipment,it is necessary to implement overall plastic forming manufacturing of the brake pad baseboard(BPB),which is the core safety component of th...To improve braking performance and achieve lightweight in transport equipment,it is necessary to implement overall plastic forming manufacturing of the brake pad baseboard(BPB),which is the core safety component of the brake system.This study presents an innovative multi-DOF envelope forming(MDFEF)process to realize the plastic forming of BPB with thin skin and high reinforcing ribs.The MDFEF principle for BPB,and the design methods for the envelope mold are first presented.Through FE simulations,the behavior of metal flow,uneven growth pattern of reinforcing ribs,evolution of equivalent strain and evolution of forming force in MDFEF of BPB are investigated.To realize MDFEF,an innovative MDFEF equipment driven by parallel linkages is exploited.The force states of linkages in MDFEF are calculated,and the reasonable mold position is determined to reduce the maximum force on the linkages and improve the service performance of MDFEF equipment.The MDFEF experiments of BPB are conducted and qualified BPB is obtained,which demonstrates that the presented MDFEF process and equipment are applicable to manufacture BPB with thin skin and high reinforcing ribs.展开更多
Obtaining zero springback and good post-form performance simultaneously is an ultimate pursuit in metal sheet forming.The stress-relaxation ageing(SRA)behavior and mechanical properties of a commercial 2219 aluminum a...Obtaining zero springback and good post-form performance simultaneously is an ultimate pursuit in metal sheet forming.The stress-relaxation ageing(SRA)behavior and mechanical properties of a commercial 2219 aluminum alloy largely pre-deformed(LPD)by 80%have been systematically investigated.The stress relaxation ratio of the LPD alloy reaches approximately 94%regardless of the initial stress(50–350 MPa)after ageing for 12 h at 140°C.This relaxation ratio is about 2.9 and 1.8 times that in the T4 tempered alloy(27.6%under 50 MPa and 31.5%under 150 MPa)and T3 tempered alloy(37.6%under 50 MPa and 51.2%under 150 MPa),respectively.The microstructures,comprised of GP zones/θ'precipitates plus dislocation tangles,and tensile properties in the stress-relaxation-aged LPD alloys remain basically invariant with different initial stresses,as is vital importance for property consistency at different locations of the formed part.Under the same SRA condition,the LPD alloy has an increase of 150–230 MPa in yield strength relative to T3/T4 tempered alloy and obtains a uniform elongation of about 8%.A simple dislocation-based constitutive model accurately describing stress relaxation enhanced by the high dislocation density is established and embedded in the finite element package through a user subroutine.Simulations and experimental verifications show the LPD alloy sheet parts exhibit a nearly zero springback(<5%)after unloading in contrast to the springback larger than 65%in the T3/T4 alloy sheet parts under the same condition.Our findings demonstrate the high-dislocation-density-enhanced SRA response enables a high-performance springback-free age forming of Al alloy sheet.展开更多
Four different types of film-forming agents were added to the foundation formulations,and their effects on the makeup-holding properties of the foundations on human facial skin were determined by Visia-CR.The study sh...Four different types of film-forming agents were added to the foundation formulations,and their effects on the makeup-holding properties of the foundations on human facial skin were determined by Visia-CR.The study showed that there was a significant difference between the sample group with film-forming agent and the blank control group,indicating that the addition of film-forming agent had an effect on the makeup-holding performance of the foundation;the makeup-holding effect of the foundation formulated with trimethylsiloxysilicate or(acrylates/dimethicone copolymer,cyclopentasiloxane)was better than that of the foundation formulated with polymethylsilsesquioxane or VP/hexadecene copolymer.This experiment is of guidance significance for the formulation design of long-lasting foundation.展开更多
With the generation of both localised thermal and vibration in incremental sheet forming(ISF)by novel tool designs,rotational vibration assisted ISF(RV-ISF)can achieve significant force reduction and material softenin...With the generation of both localised thermal and vibration in incremental sheet forming(ISF)by novel tool designs,rotational vibration assisted ISF(RV-ISF)can achieve significant force reduction and material softening.However,the combined thermal and vibration softening in RV-ISF is unclear.By evaluating the similarities and differences of friction stir ISF(FS-ISF)and RV-ISF,this study develops a novel approach to decouple and quantify the thermal and vibration softening effects in RV-ISF of AZ31B-H24,providing new insights into underlying thermal and vibration softening mechanism.Experimental results reveal that in RV-ISF of AZ31B-H24 the thermal softening due to frictional heating dominates with 45∼65%of softening,while the vibration effect only contributes up to 15%of softening,from the conventional ISF,depending on the tool designs and tool rotational speed.The double-offset tool(T2)produces greater vibration softening than the three-groove tool(T3)owing to the higher vibration amplitude of the T2 tool.An increase in tool rotational speed primarily enhances thermal softening with only marginal changes to the vibration effect.Microstructural analysis suggests that with average grain size of 0.94μm at the top layer,RV-ISF with T3 and 3000 rpm is more effective for microstructure refinement than that by FS-ISF,especially on the tool-sheet contact surface,which confirms the occurrence of surface shearing.This refinement is a result of the reduced recrystallisation degree,71.8%at the top bottom layer.Compared with FS-ISF,RV-ISF can lead to not only higher geometrically necessary dislocation density,but also higher fraction of low-angle grain boundaries,indicating that softening mechanism due to localised vibration effect is resulted from the enhanced rearrangement and annihilation of dislocations.These findings contribute to new understanding of the thermal and vibration softening effects in RV-ISF of AZ31B-H24 and offer a theoretical foundation for the tool design and process optimisation.展开更多
The glass-forming ability(GFA)of metallic glasses is a key scientific challenge in their development and application,with compositional dependence playing a crucial role.Experimental studies have demonstrated that the...The glass-forming ability(GFA)of metallic glasses is a key scientific challenge in their development and application,with compositional dependence playing a crucial role.Experimental studies have demonstrated that the addition of specific minor elements can greatly enhance the GFA of parent alloys,yet the underlying mechanism remains unclear.In this study,we use the ZrCuAl system as a model to explore how the addition of minor Al influences the crystallization rate by modulating the properties of the crystal-liquid interface,thereby affecting the GFA.The results reveal that the minor addition of Al significantly reduces the crystal growth rate,a phenomenon not governed by particle density fluctuations at the interface.The impact of minor element additions extends beyond a modest increase in crystal-unfavorable motifs in the bulk supercooled liquid.More importantly,it leads to a significant enrichment of these motifs at the crystal-supercooled liquid interface,forming a dense topological network of crystal-unfavorable structures that effectively prevent the growth of the crystalline interface and enhance GFA.Our results provide valuable insights for the design and development of high-performance metallic glasses.展开更多
Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FML...Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FMLs possess complex interlayer stresses and low forming limits,restricting further promotion and application of FMLs.Low-constraint FMLs exhibit a lower forming resistance and better formability due to no curing during the forming process;however,the formation mechanism and response are not clear.This paper presents the Forming Limit Diagram(FLD)of low-constraint GLARE(glass fiber reinforced aluminum laminates)based on the forming limit test,and compares it with the conventionally cured laminates to evaluate the differences in the forming limit.In addition,combined with the analysis of failure mechanism and micro-deformation mechanism of specimens,the influence of different temperatures(20–80℃)and forming states(width)on the deformation performance of laminates is further explored.The results reveal that the forming limit curve of low-constraint laminates shifts up with the increase of temperature,the forming limit initially increases with the increase of width,then followed by a gradual decrease,and the maximum principal strain of low-constraint laminates is increased by 29% at 80℃ compared to 20℃.The cured laminate has a principal strain range of 0–0.02,while the low-constraint laminates have a principal strain range of 0.03–0.14.Compared with cured laminates,low-constraint laminates possess a higher forming limit due to the improvement in deformable degree between layers by resin flow and fiber slippage,which enhances their formability.This study is expected to serve as a reference for establishing forming limit criteria and optimizing forming schemes for low-constraint laminates.展开更多
Laminated metal composites(LMCs)have widespread application prospects and are set to become indispensable in addressing modern engineering challenges owing to their capability of leveraging the synergy between differe...Laminated metal composites(LMCs)have widespread application prospects and are set to become indispensable in addressing modern engineering challenges owing to their capability of leveraging the synergy between different metals and tailoring performance by flexibly regulating the layered configuration.The plastic forming process,as a promising advanced manufacturing technology,has been increasingly adopted for the fabrication of LMC components due to its advantages of high material utilization rate,high production efficiency,and excellent mechanical properties of the product.This review delved into the research progress on the plastic-forming process of LMCs,including rolling,extrusion,spinning,etc.It outlined the forming principles,unique characteristics,bonding mechanisms,and the influence of key process parameters on deformation,microstructure,and property.This review focused on the heterogeneous deformation and interfacial regulation of LMCs,providing insights into the mechanisms of heterogeneous deformation,damage and fracture,and formation mechanisms of intermetallic compounds.It also delineated the experimental characterization and numerical modeling methods to elucidate the heterogeneous deformation behavior,as well as the approaches to evaluating and enhancing the performance of LMCs.Finally,the challenges and prospects of manufacturing high-performance LMCs by plastic forming process are orchestrated.展开更多
The current research on the manufacturing of large-scale and complex components focuses mainly on the casting processes.Compared with casting,plastic forming has significant advantages in terms of performance.However,...The current research on the manufacturing of large-scale and complex components focuses mainly on the casting processes.Compared with casting,plastic forming has significant advantages in terms of performance.However,effectively controlling the material flow to achieve a reduced loading force and near-uniformity in the isothermal plastic forming process of large-scale asymmetric magnesium alloy complex housings(LSMACHs)is challenging.This study proposes a material flow control method based on the diffluence upsetting-extrusion forming(DUEF)process by dividing different forging deformation regions,combining these with the principal stress method,and establishing an efficient and accurate design procedure.A rational preformed billet was designed successfully using this method.Subsequently,a finite element simulation was employed to analyze the multiphysics fields of the DUEF process.The results indicated that compared with the traditional closed-die forging(TCDF)process,the DUEF process could control the orderly flow of materials,achieve short-distance filling of materials,and reduce hydrostatic stress.Simultaneously,it improved the deformation uniformity by 20.3%and reduced the loading force by 22.6%.Finally,the rationality of the proposed method was validated through physical experiments.Compared with the TCDF process,the DUEF process exhibited a low loading force and uniform mechanical properties.The proposed material flow control method based on the DUEF process provides a new technological approach for the plastic formation of LSMACH and similar components.展开更多
To achieve the manufacturing of Thin-Wall and High-Rib Components(TWHRC)with high precision,a novel heavy load Multi-DOF Envelope Forming Press(MEFP)with Parallel Kinematic Mechanism(PKM),driven by six Permanent Magne...To achieve the manufacturing of Thin-Wall and High-Rib Components(TWHRC)with high precision,a novel heavy load Multi-DOF Envelope Forming Press(MEFP)with Parallel Kinematic Mechanism(PKM),driven by six Permanent Magnet Synchronous Motors(PMSMs),is developed.However,on account of the heavy forming load,the PMSM parameters are in great variation.Meanwhile,the PMSM is always in a transient state caused by fast time-varying forming load,resulting in low identification precision of varied PMSM parameters and control precision of PMSM under traditional parameter identification methods.To solve this problem,a novel Sliding Mode Control Method with Enhanced PMSM Parameter Identification(SMCMEPPI)for heavy load MEFP is proposed.Firstly,the kinematic model of MEFP is established.Secondly,the variation law of PMSM parameters under heavy load is revealed.Thirdly,an enhanced PMSM parameter identification method is proposed,in which the q axis current of PMSM is used to represent the changing rate of forming load and the adjustment factor is first proposed to remove improper input of PMSM parameter identification online.Fourthly,the Electromechanical Coupling Dynamic Model(ECDM)of MEFP,which includes identified PMSM parameters,is developed.Finally,based on the developed ECDM,a novel SMCMEPPI is proposed to realize the high-precision control of heavy load MEFP.The experimental results indicate that the proposed SMCMEPPI can significantly improve the control precision of heavy load MEFP.展开更多
基金supported in part by financial support from the National Key R&D Program of China(No.2023YFB3407003)the National Natural Science Foundation of China(No.52375378).
文摘A new analytical model for geometric size and forming force prediction in incremental flanging(IF)is presented in this work.The complex deformation characteristics of IF are considered in the modeling process,which can accurately describe the strain and stress states in IF.Based on strain analysis,the model can predict the material thickness distribution and neck height after IF.By considering contact area,strain characteristics,material thickness changes,and friction,the model can predict specific moments and corresponding values of maximum axial forming force and maximum horizontal forming force during IF.In addition,an IF experiment involving different tool diameters,flanging diameters,and opening hole diameters is conducted.On the basis of the experimental strain paths,the strain characteristics of different deformation zones are studied,and the stable strain ratio is quantitatively described through two dimensionless parameters:relative tool diameter and relative hole diameter.Then,the changing of material thickness and forming force in IF,and the variation of minimum material thickness,neck height,maximum axial forming force,and maximum horizontal forming force with flanging parameters are studied,and the reliability of the analytical model is verified in this process.Finally,the influence of the horizontal forming force on the tool design and the fluctuation of the forming force are explained.
基金granted by the Xinjiang Geological Exploration Fund。
文摘The northwestern margin of Junggar Basin is the region with the richest oil sand resources in China.For better understanding the enrichment rules and deployment of exploration and development of regional oil sand,it is of great scientific significance to study the accumulation conditions of oil sand in different strata and mining areas of the Junggar Basin.Through a large number of field investigations,drilling verification and sampling tests,it is found that the oil sand in the region covers an area of 2000 km^(2),with shallow and thick reservoir,and predicted resource of 180 million tons.The oil sand resources are mainly distributed in four geological strata,namely the Middle Triassic Karamay Formation,Early Jurassic Badaowan Formation,Late Jurassic Qigu Formation,and Early Cretaceous Qingshuihe Formation.The reservoir is mainly composed of sandstone with high porosity and permeability,and the reservoir space is mainly intergranular pores with a medium average oil content.The oil sand deposit in the region is a typical destructive oil reservoir.The crude oil in the oil sand layer is degraded and thickened from the deep to the shallow,the content of saturated hydrocarbon decreased,and the content of aromatic hydrocarbon,non-hydrocarbon and asphaltene increased.The oil source comes from the deep Permian hydrocarbon-generating depression.Unconformities,faults and marginal fan delta-braided river depositional systems constitute effective migration and storage systems.Caprocks of the Upper Triassic Baijiantan Formation,Lower Jurassic Sangonghe Formation and Lower Cretaceous Hutubihe Formation were formed by three large scale lake transgressions.The Indosinian,Yanshan and Late Yanshan movements are the main driving forces for the migration of deep oil and gas to the shallow edge to form oil sand deposits.It is considered that the oil sand in the northwestern margin of Junggar Basin is of a slope complex migration type.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.U1906233 and 52201312)Dalian High-Level Talent Innovation Program(Grant No.2021RD16)the Natural Science Foundation of Liaoning Province of China(Grant No.2023-BSBA-052).
文摘The carcass layer is the innermost structure of flexible marine risers and is responsible for resisting external pressure.It has an“S”section with a spiral interlocking feature.After the multi-pass roll forming of a flat steel strip,a carcass layer is formed by lock forming.During roll forming,the steel strip undergoes significant plastic deformation,and its local area accumulates residual stress owing to multiple loading and unloading cycles.These phenomena complicate the design and analysis of the carcass layer multi-pass roll forming(CLMRF)process and cause issues in the carcass layer during manufacturing,such as strip fracture and low forming quality.Thus,herein,CLMRF was investigated to clarify the stress distribution,and a parameter analysis was performed.First,the CLMRF process was designed on the basis of classical roll-forming design theory.Second,a finite element model was established,and CLMRF was simulated.Third,the distributions of the forming stress and residual stress of the strip during CLMRF were investigated.Finally,the influences of the strip thickness,roll gap,roll distance,and angular increment were investigated.The conclusions of this study can be used to provide technical guidance in the manufacturing of flexible risers.
基金the National Science and Technology Major Project of China(No.2019-VII0017e0158)the National Natural Science Foundation of China(No.U21A20131)+1 种基金the Industry-University Research Cooperation Project,China(No.HFZL2020CXY025)the National Key Laboratory of Science and Technology on Helicopter Transmission,China(No.HTL-O-21G05).
文摘Spiral bevel gears are critical transmission components,and are widely used in the aerospace field.This paper proposes a new multi-DOF envelope forming process for fabricating spiral bevel gears.Firstly,the multi-DOF envelope forming principle of spiral bevel gears is proposed.Secondly,the design methods for the envelope tool geometry and movement are proposed based on the envelope geometry and movement relationships.Thirdly,the metal flow and tooth filling laws are revealed through 3D FE simulation of the multi-DOF envelope forming process of a typical spiral bevel gear.Fourthly,a new method for separating the envelope tool and the formed spiral bevel gear with back taper tooth is proposed to avoid their interference.Finally,experiments on multi-DOF envelope forming of this typical spiral bevel gear are conducted using new heavy load multi-DOF envelope forming equipment.The simulation and experimental results show the feasibility of the proposed multi-DOF envelope forming process for fabricating spiral bevel gears with back taper tooth and the corresponding process design methods.
基金the support of the Key Research and Development Program of Shaanxi Province,China(No.2021GXLH-Z-049)。
文摘The influence of geometric configuration on the friction characteristics during incremental sheet forming of AA5052 was analyzed by integrating surface morphology and its characteristic parameters,along with plastic strain,contact pressure,and area.The interface promotes lubrication and support when wall angles were≤40°,a 0.5 mm-thin sheet was used,and a 10 mm-large tool radius was employed.This mainly results in micro-plowing and plastic extrusion flow,leading to lower friction coefficient.However,when wall angles exceed 40°,significant plastic strain roughening occurs,leading to inadequate lubrication on the newly formed surface.Increased sheet thickness and decreased tool radius elevate contact pressure.These actions trigger micro-cutting and adhesion,potentially leading to localized scuffing and dimple tears,and higher friction coefficient.The friction mechanisms remain unaffected by the part’s plane curve features.As the forming process progresses,abrasive wear intensifies,and surface morphology evolves unfavorably for lubrication and friction reduction.
基金Project(4013311)supported by the National Science Foundation of Iran(INSF)。
文摘This article examines the influence of annealing temperature on fracture toughness and forming limit curves of dissimilar aluminum/silver sheets.In the cold roll bonding process,after brushing and acid washing,the prepared surfaces are placed on top of each other and by rolling with reduction more than 50%,the bonding between layers is established.In this research,the roll bonding process was done at room temperature,without the use of lubricants and with a 70%thickness reduction.Then,the final thickness of the Ag/Al bilayer sheet reached 350μm by several stages of cold rolling.Before cold rolling,it should be noted that to decrease the hardness created due to plastic deformation,the roll-bonded samples were subjected to annealing heat treatment at 400℃for 90 min.Thus,the final samples were annealed at 200,300 and 400℃for 90 min and cooled in a furnace to examine the annealing temperature effects.The uniaxial tensile and microhardness tests measured mechanical properties.Also,to investigate the fracture mechanism,the fractography of the cross-section was examined by scanning electron microscope(SEM).To evaluate the formability of Ag/Al bilayer sheets,forming limit curves were obtained experimentally through the Nakazima test.The resistance of composites to failure due to cracking was also investigated by fracture toughness.The results showed that annealing increases the elongation and formability of the Ag/Al bilayer sheet while reduces the ultimate tensile strength and fracture toughness.However,the changing trend is not the same at different temperatures,and according to the results,the most significant effect is obtained at 300℃and aluminum layers.It was also determined that by increasing annealing temperature,the fracture mechanism from shear ductile with small and shallow dimples becomes ductile with deep cavities.
基金Shaanxi Province Qin Chuangyuan“Scientist+Engineer”Team Construction Project(2022KXJ-071)2022 Qin Chuangyuan Achievement Transformation Incubation Capacity Improvement Project(2022JH-ZHFHTS-0012)+1 种基金Shaanxi Province Key Research and Development Plan-“Two Chains”Integration Key Project-Qin Chuangyuan General Window Industrial Cluster Project(2023QCY-LL-02)Xixian New Area Science and Technology Plan(2022-YXYJ-003,2022-XXCY-010)。
文摘To overcome the shortage of complex equipment,large volume,and high energy consumption in space capsule manufacturing,a novel sliding pressure Joule heat fuse additive manufacturing technique with reduced volume and low energy consumption was proposed.But the unreasonable process parameters may lead to the inferior consistency of the forming quality of single-channel multilayer in Joule heat additive manufacturing process,and it is difficult to reach the condition for forming thinwalled parts.Orthogonal experiments were designed to fabricate single-channel multilayer samples with varying numbers of layers,and their forming quality was evaluated.The influence of printing current,forming speed,and contact pressure on the forming quality of the single-channel multilayer was analyzed.The optimal process parameters were obtained and the quality characterization of the experiment results was conducted.Results show that the printing current has the most significant influence on the forming quality of the single-channel multilayer.Under the optimal process parameters,the forming section is well fused and the surface is continuously smooth.The surface roughness of a single-channel 3-layer sample is 0.16μm,and the average Vickers hardness of cross section fusion zone is 317 HV,which lays a foundation for the subsequent use of Joule heat additive manufacturing technique to form thinwall parts.
基金National Key Research and Development Program(2021YFB3401101)。
文摘Short process forming techniques for brazing and soldering materials can shorten the process,improve product quality,and increase production efficiency,which has received much attention from welding researchers.This review mainly summarized the research reports on short process forming techniques for brazing and soldering materials.Firstly,the traditional process and its shortcomings were presented.Secondly,the latest research of short process forming technologies,such as continuous casting technique,atomization powder technique,solder ball forming technique,and rapid solidification technique,was summarized,and the traditional forming performance of several brazing and soldering materials was introduced.Finally,the current restrictions and research trends of short process forming technique for brazing and solder materials were put forward,providing theoretical guidance and reference for related research and technique development in brazing and soldering field.
基金the National Key R&D Program of China(No.2023YFB3407003)the National Natural Science Foundation of China(No.52375378).
文摘An analytical model for contact area and contact stress considering the loading history in incremental sheet forming(ISF)was established.Then,by integrating with the directional characteristics of friction force and horizontal force in the process,a friction test method reflecting the forming characteristics of ISF was proposed.Friction coefficients during the forming processes of parts with different wall angles were measured under various plane curves,process paths,and lubrication conditions.Furthermore,the accuracy of the analytical model,as well as the measured friction coefficients and their variation trends,was verified through comparative analysis with experimental results,simulation data,and outcomes from other existing models.The results indicate that the influence of the plane curve characteristics and process paths of parts on the friction condition is not significant.Under the lubrication conditions of L-HM46 oil,MoS_(2)grease,graphite powder,and dry friction,the friction coefficient shows a gradually increasing trend.Notably,when the wall angle is≤40°,the friction coefficient remains relatively constant;however,when the wall angle exceeds 40°,the friction coefficient increases progressively.
基金Science and Technology Planning Project of Inner Mongolia Science and Technology Department(2022YFSH0021)Key Research and Development Program of Shaanxi Province(2024SF2-GJHX-14,2021SF-296)。
文摘Four types of Mg-5Zn porous scaffolds with different pore geometries,including body-centered cubic(bcc),the rhombic dodecahedron(RD),gyroid(G),and primitive(P)types,were designed and fabricated using selective laser melting.Their forming quality,compression mechanical properties,and degradation behavior were investigated.Results indicate that the fabricated scaffolds exhibit good dimensional accuracy,and the surface chemical polishing treatment significantly improves the forming quality and reduces porosity error in porous scaffolds.Compared to the ones with rod structures(bcc,RD),the scaffolds with surface structures(G,P)have less powder particle adhesion.The G porous scaffold exhibits the best forming quality for the same design porosity.The predominant failure mode of scaffolds during compression is a 45°shear fracture.At a porosity of 75%,the compression property of all scaffolds meets the compressive property requirements of cancellous bone,while bcc and G structures show relatively better compression property.After immersion in Hank's solution for 168 h,the B-2-75% pore structure scaffold exhibits severe localized corrosion,with fractures in partial pillar connections.In contrast,the G-3-75% pore structure scaffold mainly undergoes uniform corrosion,maintaining structural integrity,and its corrosion rate and loss of compressive properties are less than those of the B-2-75%structure.After comparison,the G-pore structure scaffold is preferred.
基金supported by the National Natural Science Foundation of China(62403296,62303292,62173218).
文摘Dear Editor,This letter investigates the grid-forming control for power converters.Recently,grid-forming control based on matching of synchronous machines was suggested by using continuous measurements.In the present letter,we suggest a digital implementation using artificial delays where the controller employs the discrete-time measurements only.
基金Supported by National Natural Science Foundation of China(Grant No.U21A20131)Innovative Research Team Development Program of Ministry of Education of China(Grant No.IRT17R83)111 Project(Grant No.B17034)。
文摘To improve braking performance and achieve lightweight in transport equipment,it is necessary to implement overall plastic forming manufacturing of the brake pad baseboard(BPB),which is the core safety component of the brake system.This study presents an innovative multi-DOF envelope forming(MDFEF)process to realize the plastic forming of BPB with thin skin and high reinforcing ribs.The MDFEF principle for BPB,and the design methods for the envelope mold are first presented.Through FE simulations,the behavior of metal flow,uneven growth pattern of reinforcing ribs,evolution of equivalent strain and evolution of forming force in MDFEF of BPB are investigated.To realize MDFEF,an innovative MDFEF equipment driven by parallel linkages is exploited.The force states of linkages in MDFEF are calculated,and the reasonable mold position is determined to reduce the maximum force on the linkages and improve the service performance of MDFEF equipment.The MDFEF experiments of BPB are conducted and qualified BPB is obtained,which demonstrates that the presented MDFEF process and equipment are applicable to manufacture BPB with thin skin and high reinforcing ribs.
基金financially supported by the National Natural Science Foundation of China(Nos.52274404,52305441,and U22A20190)the Natural Science Foundation of Hunan province(Nos.2022JJ20065 and 2023JJ40739)+1 种基金the Science and Technology Innovation Program of Hunan Province(No.2022RC1001)the National Key R&D Program of China(No.2021YFB3400903).
文摘Obtaining zero springback and good post-form performance simultaneously is an ultimate pursuit in metal sheet forming.The stress-relaxation ageing(SRA)behavior and mechanical properties of a commercial 2219 aluminum alloy largely pre-deformed(LPD)by 80%have been systematically investigated.The stress relaxation ratio of the LPD alloy reaches approximately 94%regardless of the initial stress(50–350 MPa)after ageing for 12 h at 140°C.This relaxation ratio is about 2.9 and 1.8 times that in the T4 tempered alloy(27.6%under 50 MPa and 31.5%under 150 MPa)and T3 tempered alloy(37.6%under 50 MPa and 51.2%under 150 MPa),respectively.The microstructures,comprised of GP zones/θ'precipitates plus dislocation tangles,and tensile properties in the stress-relaxation-aged LPD alloys remain basically invariant with different initial stresses,as is vital importance for property consistency at different locations of the formed part.Under the same SRA condition,the LPD alloy has an increase of 150–230 MPa in yield strength relative to T3/T4 tempered alloy and obtains a uniform elongation of about 8%.A simple dislocation-based constitutive model accurately describing stress relaxation enhanced by the high dislocation density is established and embedded in the finite element package through a user subroutine.Simulations and experimental verifications show the LPD alloy sheet parts exhibit a nearly zero springback(<5%)after unloading in contrast to the springback larger than 65%in the T3/T4 alloy sheet parts under the same condition.Our findings demonstrate the high-dislocation-density-enhanced SRA response enables a high-performance springback-free age forming of Al alloy sheet.
文摘Four different types of film-forming agents were added to the foundation formulations,and their effects on the makeup-holding properties of the foundations on human facial skin were determined by Visia-CR.The study showed that there was a significant difference between the sample group with film-forming agent and the blank control group,indicating that the addition of film-forming agent had an effect on the makeup-holding performance of the foundation;the makeup-holding effect of the foundation formulated with trimethylsiloxysilicate or(acrylates/dimethicone copolymer,cyclopentasiloxane)was better than that of the foundation formulated with polymethylsilsesquioxane or VP/hexadecene copolymer.This experiment is of guidance significance for the formulation design of long-lasting foundation.
基金the financial support received from the UK Engineering and Physical Sciences Research Council(EPSRC)through project grants EP/W010089/1 and EP/T005254/1.
文摘With the generation of both localised thermal and vibration in incremental sheet forming(ISF)by novel tool designs,rotational vibration assisted ISF(RV-ISF)can achieve significant force reduction and material softening.However,the combined thermal and vibration softening in RV-ISF is unclear.By evaluating the similarities and differences of friction stir ISF(FS-ISF)and RV-ISF,this study develops a novel approach to decouple and quantify the thermal and vibration softening effects in RV-ISF of AZ31B-H24,providing new insights into underlying thermal and vibration softening mechanism.Experimental results reveal that in RV-ISF of AZ31B-H24 the thermal softening due to frictional heating dominates with 45∼65%of softening,while the vibration effect only contributes up to 15%of softening,from the conventional ISF,depending on the tool designs and tool rotational speed.The double-offset tool(T2)produces greater vibration softening than the three-groove tool(T3)owing to the higher vibration amplitude of the T2 tool.An increase in tool rotational speed primarily enhances thermal softening with only marginal changes to the vibration effect.Microstructural analysis suggests that with average grain size of 0.94μm at the top layer,RV-ISF with T3 and 3000 rpm is more effective for microstructure refinement than that by FS-ISF,especially on the tool-sheet contact surface,which confirms the occurrence of surface shearing.This refinement is a result of the reduced recrystallisation degree,71.8%at the top bottom layer.Compared with FS-ISF,RV-ISF can lead to not only higher geometrically necessary dislocation density,but also higher fraction of low-angle grain boundaries,indicating that softening mechanism due to localised vibration effect is resulted from the enhanced rearrangement and annihilation of dislocations.These findings contribute to new understanding of the thermal and vibration softening effects in RV-ISF of AZ31B-H24 and offer a theoretical foundation for the tool design and process optimisation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.T2325004 and 52161160330)the support from the Hong Kong Institute of Advanced Studies through the materials cluster project。
文摘The glass-forming ability(GFA)of metallic glasses is a key scientific challenge in their development and application,with compositional dependence playing a crucial role.Experimental studies have demonstrated that the addition of specific minor elements can greatly enhance the GFA of parent alloys,yet the underlying mechanism remains unclear.In this study,we use the ZrCuAl system as a model to explore how the addition of minor Al influences the crystallization rate by modulating the properties of the crystal-liquid interface,thereby affecting the GFA.The results reveal that the minor addition of Al significantly reduces the crystal growth rate,a phenomenon not governed by particle density fluctuations at the interface.The impact of minor element additions extends beyond a modest increase in crystal-unfavorable motifs in the bulk supercooled liquid.More importantly,it leads to a significant enrichment of these motifs at the crystal-supercooled liquid interface,forming a dense topological network of crystal-unfavorable structures that effectively prevent the growth of the crystalline interface and enhance GFA.Our results provide valuable insights for the design and development of high-performance metallic glasses.
基金supported by the National Natural Science Fund of China(Nos.52005153,12227801,32300666,12072005,U23A2607)the Tianjin"Project+Team"Key Training Program,China(No.XC202052)+4 种基金the Key Program of Research and Development of Hebei Province,China(Nos.202030507040009,23311812D)the Natural Science Foundation of Hebei Province,China(No.E2023202183)the Project of High-Level Team Construction Introduction of Hebei Province,China(No.244A7620D)the Research Cooperation Project of Universities Stationed in Hebei Province and Shijiazhuang City,China(No.241080114A)Hebei Province Military-Civilian Integration Science and Technology Innovation Project,China(No.SJMYF2022X15)。
文摘Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FMLs possess complex interlayer stresses and low forming limits,restricting further promotion and application of FMLs.Low-constraint FMLs exhibit a lower forming resistance and better formability due to no curing during the forming process;however,the formation mechanism and response are not clear.This paper presents the Forming Limit Diagram(FLD)of low-constraint GLARE(glass fiber reinforced aluminum laminates)based on the forming limit test,and compares it with the conventionally cured laminates to evaluate the differences in the forming limit.In addition,combined with the analysis of failure mechanism and micro-deformation mechanism of specimens,the influence of different temperatures(20–80℃)and forming states(width)on the deformation performance of laminates is further explored.The results reveal that the forming limit curve of low-constraint laminates shifts up with the increase of temperature,the forming limit initially increases with the increase of width,then followed by a gradual decrease,and the maximum principal strain of low-constraint laminates is increased by 29% at 80℃ compared to 20℃.The cured laminate has a principal strain range of 0–0.02,while the low-constraint laminates have a principal strain range of 0.03–0.14.Compared with cured laminates,low-constraint laminates possess a higher forming limit due to the improvement in deformable degree between layers by resin flow and fiber slippage,which enhances their formability.This study is expected to serve as a reference for establishing forming limit criteria and optimizing forming schemes for low-constraint laminates.
基金supported by the National Natural Science Foundation of China(Grant Nos.52305361,52105337,52475354,and 52090043)the BK21 Four program(SNU Materials Education/Research Division for Creative Global Leaders)+1 种基金the China Postdoctoral Science Foundation(Grant No.2023M741245),and the National Key Research and Development Program of China(Grant No.2022YFB3706903)support from the Ko-rean Ministry of Trade,Industry and Energy(MOTIE,Korea)(Grant No.20022438).
文摘Laminated metal composites(LMCs)have widespread application prospects and are set to become indispensable in addressing modern engineering challenges owing to their capability of leveraging the synergy between different metals and tailoring performance by flexibly regulating the layered configuration.The plastic forming process,as a promising advanced manufacturing technology,has been increasingly adopted for the fabrication of LMC components due to its advantages of high material utilization rate,high production efficiency,and excellent mechanical properties of the product.This review delved into the research progress on the plastic-forming process of LMCs,including rolling,extrusion,spinning,etc.It outlined the forming principles,unique characteristics,bonding mechanisms,and the influence of key process parameters on deformation,microstructure,and property.This review focused on the heterogeneous deformation and interfacial regulation of LMCs,providing insights into the mechanisms of heterogeneous deformation,damage and fracture,and formation mechanisms of intermetallic compounds.It also delineated the experimental characterization and numerical modeling methods to elucidate the heterogeneous deformation behavior,as well as the approaches to evaluating and enhancing the performance of LMCs.Finally,the challenges and prospects of manufacturing high-performance LMCs by plastic forming process are orchestrated.
基金Supported by National Natural Science Foundation of China(Grant No.52075501).
文摘The current research on the manufacturing of large-scale and complex components focuses mainly on the casting processes.Compared with casting,plastic forming has significant advantages in terms of performance.However,effectively controlling the material flow to achieve a reduced loading force and near-uniformity in the isothermal plastic forming process of large-scale asymmetric magnesium alloy complex housings(LSMACHs)is challenging.This study proposes a material flow control method based on the diffluence upsetting-extrusion forming(DUEF)process by dividing different forging deformation regions,combining these with the principal stress method,and establishing an efficient and accurate design procedure.A rational preformed billet was designed successfully using this method.Subsequently,a finite element simulation was employed to analyze the multiphysics fields of the DUEF process.The results indicated that compared with the traditional closed-die forging(TCDF)process,the DUEF process could control the orderly flow of materials,achieve short-distance filling of materials,and reduce hydrostatic stress.Simultaneously,it improved the deformation uniformity by 20.3%and reduced the loading force by 22.6%.Finally,the rationality of the proposed method was validated through physical experiments.Compared with the TCDF process,the DUEF process exhibited a low loading force and uniform mechanical properties.The proposed material flow control method based on the DUEF process provides a new technological approach for the plastic formation of LSMACH and similar components.
基金the National Science and Technology Major Project of China(No.2019-Ⅶ-0017-0158)the National Natural Science Foundation of China(Nos.U2037204,U21A20131)the Innovative Research Team Development Program of Ministry of Education of China(No.IRT17R83)for the support given to this research。
文摘To achieve the manufacturing of Thin-Wall and High-Rib Components(TWHRC)with high precision,a novel heavy load Multi-DOF Envelope Forming Press(MEFP)with Parallel Kinematic Mechanism(PKM),driven by six Permanent Magnet Synchronous Motors(PMSMs),is developed.However,on account of the heavy forming load,the PMSM parameters are in great variation.Meanwhile,the PMSM is always in a transient state caused by fast time-varying forming load,resulting in low identification precision of varied PMSM parameters and control precision of PMSM under traditional parameter identification methods.To solve this problem,a novel Sliding Mode Control Method with Enhanced PMSM Parameter Identification(SMCMEPPI)for heavy load MEFP is proposed.Firstly,the kinematic model of MEFP is established.Secondly,the variation law of PMSM parameters under heavy load is revealed.Thirdly,an enhanced PMSM parameter identification method is proposed,in which the q axis current of PMSM is used to represent the changing rate of forming load and the adjustment factor is first proposed to remove improper input of PMSM parameter identification online.Fourthly,the Electromechanical Coupling Dynamic Model(ECDM)of MEFP,which includes identified PMSM parameters,is developed.Finally,based on the developed ECDM,a novel SMCMEPPI is proposed to realize the high-precision control of heavy load MEFP.The experimental results indicate that the proposed SMCMEPPI can significantly improve the control precision of heavy load MEFP.
