To detect space gravitational waves in the extremely low-frequency band,the telescope and optic-al platform require high stability and reliability.However,the cantilevered design presents challenges,espe-cially in the...To detect space gravitational waves in the extremely low-frequency band,the telescope and optic-al platform require high stability and reliability.However,the cantilevered design presents challenges,espe-cially in the glass-metal hetero-bonding process.This study focuses on the analysis and experimental re-search of the bonding layer in the integrated structure.By optimizing the structural configuration and select-ing suitable bonding processes,the reliability of the telescope system is enhanced.The research indicates that using J-133 adhesive achieves the best performance,with a bonding layer thickness of 0.30 mm and a metal substrate surface roughness of Ra 0.8.These findings significantly enhance the reliability of the optical sys-tem while minimizing potential risks.展开更多
To ensure the structural integrity of life-limiting component of aeroengines,Probabilistic Damage Tolerance(PDT)assessment is applied to evaluate the failure risk as required by airworthiness regulations and military ...To ensure the structural integrity of life-limiting component of aeroengines,Probabilistic Damage Tolerance(PDT)assessment is applied to evaluate the failure risk as required by airworthiness regulations and military standards.The PDT method holds the view that there exist defects such as machining scratches and service cracks in the tenon-groove structures of aeroengine disks.However,it is challenging to conduct PDT assessment due to the scarcity of effective Probability of Detection(POD)model and anomaly distribution model.Through a series of Nondestructive Testing(NDT)experiments,the POD model of real cracks in tenon-groove structures is constructed for the first time by employing the Transfer Function Method(TFM).A novel anomaly distribution model is derived through the utilization of the POD model,instead of using the infeasible field data accumulation method.Subsequently,a framework for calculating the Probability of Failure(POF)of the tenon-groove structures is established,and the aforementioned two models exert a significant influence on the results of POF.展开更多
Background Cetobacterium somerae,a symbiotic microorganism resident in various fish intestines,is recognized for its beneficial effects on fish gut health.However,the mechanisms underlying the effects of C.somerae on ...Background Cetobacterium somerae,a symbiotic microorganism resident in various fish intestines,is recognized for its beneficial effects on fish gut health.However,the mechanisms underlying the effects of C.somerae on gut health remain unclear.In this experiment,we investigated the influence of C.somerae(CGMCC No.28843)on the growth performance,intestinal digestive and absorptive capacity,and intestinal structural integrity of juvenile grass carp(Ctenopharyngodon idella)and explored its potential mechanisms.Methods A cohort of 2,160 juvenile grass carp with an initial mean body weight of 11.30±0.01 g were randomly allocated into 6 treatment groups,each comprising 6 replicates(60 fish per replicate).The experimental diets were supplemented with C.somerae at graded levels of 0.00(control),0.68×10^(9),1.35×10^(9),2.04×10^(9),2.70×10^(9),and 3.40×10^(9)cells/kg feed.Following a 10-week experimental period,biological samples were collected for subsequent analyses.Results Dietary supplementation with C.somerae at 1.35×10^(9)cells/kg significantly enhanced growth performance,intestinal development,and nutrient retention rate in juvenile grass carp(P<0.05).The treatment resulted in increased intestinal acetic acid concentration and enhanced activities of digestive enzymes and brush border enzymes(P<0.05).Furthermore,it reduced intestinal permeability(P<0.05),preserved tight junctions(TJ)ultrastructural integrity,and increased the expression of TJ and adherens junctions(AJ)biomarkers at both protein and transcriptional levels(P<0.05).Mechanistically,these effects may be correlated with enhanced antioxidant capacity and coordinated modulation of the RhoA/ROCK,Sirt1,and PI3K/AKT signaling pathways.The appropriate supplementation levels,based on weight gain rate,feed conversion ratio,the activity of serum diamine oxidase and the content of lipopolysaccharide,were 1.27×10^(9),1.27×10^(9),1.34×10^(9)and 1.34×10^(9)cells/kg,respectively.Conclusions C.somerae improved intestinal digestive and absorptive capacity of juvenile grass carp,maintained intestinal structural integrity,and thus promoted their growth and development.This work demonstrates the potential of C.somerae as a probiotic for aquatic animals and provides a theoretical basis for its utilization in aquaculture.展开更多
Purpose–The safety and reliability of high-speed trains rely on the structural integrity of their components and the dynamic performance of the entire vehicle system.This paper aims to define and substantiate the ass...Purpose–The safety and reliability of high-speed trains rely on the structural integrity of their components and the dynamic performance of the entire vehicle system.This paper aims to define and substantiate the assessment of the structural integrity and dynamical integrity of high-speed trains in both theory and practice.The key principles and approacheswill be proposed,and their applications to high-speed trains in Chinawill be presented.Design/methodology/approach–First,the structural integrity and dynamical integrity of high-speed trains are defined,and their relationship is introduced.Then,the principles for assessing the structural integrity of structural and dynamical components are presented and practical examples of gearboxes and dampers are provided.Finally,the principles and approaches for assessing the dynamical integrity of highspeed trains are presented and a novel operational assessment method is further presented.Findings–Vehicle system dynamics is the core of the proposed framework that provides the loads and vibrations on train components and the dynamic performance of the entire vehicle system.For assessing the structural integrity of structural components,an open-loop analysis considering both normal and abnormal vehicle conditions is needed.For assessing the structural integrity of dynamical components,a closed-loop analysis involving the influence of wear and degradation on vehicle system dynamics is needed.The analysis of vehicle system dynamics should follow the principles of complete objects,conditions and indices.Numerical,experimental and operational approaches should be combined to achieve effective assessments.Originality/value–The practical applications demonstrate that assessing the structural integrity and dynamical integrity of high-speed trains can support better control of critical defects,better lifespan management of train components and better maintenance decision-making for high-speed trains.展开更多
The development of tissue engineering and regeneration research has created new platforms for bone transplantation.However,the preparation of scaffolds with good fiber integrity is challenging,because scaffolds prepar...The development of tissue engineering and regeneration research has created new platforms for bone transplantation.However,the preparation of scaffolds with good fiber integrity is challenging,because scaffolds prepared by traditional printing methods are prone to fiber cracking during solvent evaporation.Human skin has an excellent natural heat-management system,which helps to maintain a constant body temperature through perspiration or blood-vessel constriction.In this work,an electrohydrodynamic-jet 3D-printing method inspired by the thermal-management system of skin was developed.In this system,the evaporation of solvent in the printed fibers can be adjusted using the temperature-change rate of the substrate to prepare 3D structures with good structural integrity.To investigate the solvent evaporation and the interlayer bonding of the fibers,finite-element analysis simulations of a three-layer microscale structure were carried out.The results show that the solvent-evaporation path is from bottom to top,and the strain in the printed structure becomes smaller with a smaller temperaturechange rate.Experimental results verified the accuracy of these simulation results,and a variety of complex 3D structures with high aspect ratios were printed.Microscale cracks were reduced to the nanoscale by adjusting the temperature-change rate from 2.5 to 0.5℃s-1.Optimized process parameters were selected to prepare a tissue engineering scaffold with high integrity.It was confirmed that this printed scaffold had good biocompatibility and could be used for bone-tissue regeneration.This simple and flexible 3D-printing method can also help with the preparation of a wide range of micro-and nanostructured sensors and actuators.展开更多
This research extends ongoing efforts to develop methods for reinforcing damaged main gas pipelines to prevent catastrophic failure.This study establishes the use of scaled-down experimental models for assessing the d...This research extends ongoing efforts to develop methods for reinforcing damaged main gas pipelines to prevent catastrophic failure.This study establishes the use of scaled-down experimental models for assessing the dynamic strength of damaged pipeline sections reinforced with wire wrapping or composite sleeves.A generalized dynamic model is introduced for numerical simulation to evaluate the effectiveness of reinforcement techniques.The model incorporates the elastoplastic behavior of pipe and wire materials,the influence of temperature on mechanical properties,the contact interaction between the pipe and the reinforcement components(including pretensioning),and local material failure under transient internal pressure.Based on these parameters,a finite element model was developed using ANSYS 19.2 to enable parametric studies.The accuracy of the proposed model was verified by comparing the simulation results with the experimental findings.Pipeline section samples containing non-penetrating longitudinal crackswere subjected to comparative analyses and transient pressure until critical failure.The unreinforced and steel wire-wrapped sections were investigated.The results confirm the feasibility of applying the computational model to study the dynamic strength of reinforced damaged pipe sections.Furthermore,pipelines with longitudinal cracks reinforced using circular composite overlays with orthotropic mechanical properties were examined,and recommendations are provided for selecting the geometric parameters of such overlays.展开更多
Oxygen vacancies(Ov)within metal oxide electrodes can enhance mass/charge transfer dynamics in energy storage systems.However,construction of surface Ovoften leads to instability in electrode structure and irreversibl...Oxygen vacancies(Ov)within metal oxide electrodes can enhance mass/charge transfer dynamics in energy storage systems.However,construction of surface Ovoften leads to instability in electrode structure and irreversible electrochemical reactions,posing a significant challenge.To overcome these challenges,atomic heterostructures are employed to address the structural instability and enhance the mass/charge transfer dynamics associated with phase conversion mechanism in aqueous electrodes,Herein,we introduce an atomic S-Bi_(2)O_(3)heterostructure(sulfur(S)anchoring on the surface Ovof Bi_(2)O_(3)).The integration of S within Bi_(2)O_(3)lattice matrix triggers a charge imbala nce at the heterointerfaces,ultimately resulting in the creation of a built-in electric field(BEF).Thus,the BEF attracts OH-ions to be adsorbed onto Bi within the regions of high electron cloud overlap in S-Bi_(2)O_(3),facilitating highly efficient charge transfer.Furthermore,the anchored S plays a pivotal role in preserving structural integrity,thus effectively stabilizing the phase conversion reaction of Bi_(2)O_(3).As a result,the S-Bi_(2)O_(3)electrode achieves72.3 mA h g^(-1)at 10 A g^(-1)as well as high-capacity retention of 81.9%after 1600 cycles.Our innovative SBi_(2)O_(3)design presents a groundbreaking approach for fabricating electrodes that exhibit efficient and stable mass and charge transfer capabilities.Furthermore,it enhances our understanding of the underlying reaction mechanism within energy storage electrodes.展开更多
Ensuring the structural integrity of piping systems is crucial in industrial operations to prevent catastrophic failures and minimize shutdown time.This study investigates a transportation-damaged pipe exposed to high...Ensuring the structural integrity of piping systems is crucial in industrial operations to prevent catastrophic failures and minimize shutdown time.This study investigates a transportation-damaged pipe exposed to high-temperature conditions and cyclic loading,representing a realistic challenge in plant operation.The objective was to evaluate the service life and integrity assessment parameters of the damaged pipe,subjected to 22,000 operational cycles under two daily charge and discharge conditions.The flaw size in the damaged pipe was determined based on a failure assessment procedure,ensuring a conservative and reliable input.The damage was characterized as a long axial surface crack with a depth of a=2 mm and half-length c=50 mm(c/a=25),a geometry not well covered by existing Stress Intensity Factor solutions.To address this limitation,a modified magnification factor(M*)was introduced and tested for the present damage case(c/a=25)and for additional crack geometries(c/a=28–70),which showed improved agreement with Finite Element Analysis(FEA)than Newman’s original formulation.Stress Intensity Factor and Plastic Limit Pressure,essential parameters for structural integrity assessment,were computed numerically using FEA and validated against analytical predictions.Fatigue crack growth was evaluated using the Paris law with crack propagation simulated numerically by Ansys’s S.M.A.R.T.The Failure Assessment Diagram(FAD)was used to assess service life,incorporating constant working pressure and fracture toughness while considering evolving crack size during propagation.Results showed that analytical predictions with the modified magnification factor matched FEA within 5%,while the original Newman formulation overestimated results.The analytical service life solution predicted approximately 8500 fewer cycles than the numerical,remaining conservative but efficient.These findings are based on the present case of a long axial surface crack with high aspect ratios(c/a=25–70,depending on crack depth),and while the modified magnification factor may also improve predictions for other geometries,this requires structured validation in future studies.展开更多
To investigate the residual stress distribution and its influence on machining deformation in 6061-T651 aluminum alloy plates,this paper uses the crack compliance method to study the residual stress characteristics of...To investigate the residual stress distribution and its influence on machining deformation in 6061-T651 aluminum alloy plates,this paper uses the crack compliance method to study the residual stress characteristics of 6061-T651 aluminum alloy plates with a thickness of 75 mm produced by two domestic manufacturers in China.The results indicate that both types of plates exhibit highly consistent and symmetrical M-shaped residual stress profile along the thickness direction,manifested as surface layer compression and core tension.The strain energy density across all specimens ranges from 1.27 kJ/m^(3)to 1.43 kJ/m^(3).Machining deformation simulations of an aerospace component incorporating these measured stresses showed minimal final deformation difference between the material sources,with a maximum deviation of only 0.009 mm across specimens.These findings provide critical data for material selection and deformation control in aerospace manufacturing.展开更多
Projectiles made of reactive structure materials(RSM)can damage the target with not only kinetic but also chemical energy,but the enhanced damage potential of RSM may become compromised if extreme loading condition di...Projectiles made of reactive structure materials(RSM)can damage the target with not only kinetic but also chemical energy,but the enhanced damage potential of RSM may become compromised if extreme loading condition disintegrates the projectile before the target is reached.In this work,a ductile coating of Ni was introduced to a tungsten-zirconium(W-Zr)alloy,a typical brittle RSM,to preserve the damage potential of the projectile.Detonation driving tests were carried out with X-ray photography and gunpowder deflagration driving tests were carried out with high-speed photography for the coated and uncoated RSM samples,respectively.The craters on the witness target were analyzed by scanning electron microscopy and X-ray diffraction.The Ni coating was found to effectively preserve the damage potential of the W-Zr alloy under extreme loading conditions,whereas the uncoated sample fractured and ignited before impacting the target in both detonation and deflagration driving.The crack propagation between the reactively brittle core and the ductile coating was analyzed based on the crack arrest theory to mechanistically demonstrate how the coating improves the structural integrity and preserves the damage potential of the projectile.Specifically,the Ni coating envelops theW-Zr core until the coated sphere penetrates the target,and the coating is then eroded and worn to release the reactive core for the projectile to damage the target more intensively.展开更多
The primary objective of the present literature review is to provide a constructive and systematical discussion based on the relevant development,unsolved issues,gaps,and misconceptions in the literature regarding the...The primary objective of the present literature review is to provide a constructive and systematical discussion based on the relevant development,unsolved issues,gaps,and misconceptions in the literature regarding the fields of study that are building blocks of artificial intelligence-aided life extension assessment for offshore wind turbine support structures.The present review aims to set up the needed guidelines to develop a multi-disciplinary framework for life extension management and certification of the support structures for offshore wind turbines using artificial intelligence.The main focus of the literature review centres around the intelligent risk-based life extension management of offshore wind turbine support structures.In this regard,big data analytics,advanced signal processing techniques,supervised and unsupervised machine learning methods are discussed within the structural health monitoring and condition-based maintenance planning,the development of digital twins.Furthermore,the present review discusses the critical failure mechanisms affecting the structural condition,such as high-cycle fatigue,low-cycle fatigue,fracture,ultimate strength,and corrosion,considering deterministic and probabilistic approaches.展开更多
A-Jacks are concrete armor units that are used in both open channel and coastal applications.In open channel applications,they are used for bank and toe protection,flow and grade control,bridge pier scour protection,e...A-Jacks are concrete armor units that are used in both open channel and coastal applications.In open channel applications,they are used for bank and toe protection,flow and grade control,bridge pier scour protection,energy dissipation,and habitat.These small units may be fabricated in standard block machines.In coastal applications,A-Jacks are used in breakwaters,jetties,revetments,and habitat development.Coastal units are generally much larger and more robust than the small open channel units.This paper focuses on coastal applications and in particular,combines results on three topics:(1)recent hydraulic model studies,(2)alternative fabrication methods,and(3)bundle placement construction methods.Hydraulic models studies were conducted that examined the standard random and uniform placement methods,and also the bundle placement method.In bundle placement,3~20 A-Jacks are banded together,lifted with a spreader bar,and placed as a single crane pick.This significantly decreases installation time during construction.It also provides a more hydraulically stable placement technique.The hydraulic model tests examined the bundle stability in random waves for cases where the binding remains in tack and is removed.The geometry of A-Jacks enables a variety of fabrication techniques.One option is to fabricate the A-Jacks as two pieces using flat forms and then grout the two pieces together.Flat forms may be used in conventional block machines for A-Jacks sizes up to 1.3 m.Larger sizes may be wet cast in flat forms or gang forms.The A-Jacks geometry has been recently modified to increase grouting efficient and strength.Large A- Jacks may also be cast in a single piece using 'clam shell' type forms.展开更多
Ultra-high temperature ceramics have been considered as good candidates for plasma facing materials due to their combination of high melting point,high strength and hardness,high thermal conductivity as well as good c...Ultra-high temperature ceramics have been considered as good candidates for plasma facing materials due to their combination of high melting point,high strength and hardness,high thermal conductivity as well as good chemical inertness.In this study,zirconium diboride has been chosen to investigate its irradiation damage behavior.Irradiated by 4 MeV Au^(2+)with a total fluence of 2.5×10^(16)cm^(-2),zirconium diboride ceramic shows substantial resilience to irradiation-induced damage with its structural integrity well maintained but mild damage at lattice level.Grazing incident X-ray diffraction evidences no change of the hexagonal structure in the irradiated region but its lattice parameter a increased and c decreased,giving a volume shrinkage of 0.46%.Density functional theory calculation shows that such lattice shrinkage corresponds to a non-stoichiometric compound as ZrB1.97.Electron energy-loss spectroscopy in a transmission electron microscope revealed an increase of valence electrons in zirconium,suggesting boron vacancies were indeed developed by the irradiation.Alo ng the irradiation depth,long dislocations were observed inside top layer with a depth of 750 nm where the implanted Au ions reached the peak concentration.Underneath the top layer,a high density of Frank dislocations is formed by the cascade collision down to a depth of 1150 nm.All the features show the potential of ZrB_(2) to be used as structural material in nuclear system.展开更多
The hot or cold processing would induce the change and the inhomogeneous of the material mechanical properties in the local processing region of the structure,and it is difficult to obtain the specific mechanical prop...The hot or cold processing would induce the change and the inhomogeneous of the material mechanical properties in the local processing region of the structure,and it is difficult to obtain the specific mechanical properties in these regions by using the traditional material tensile test.To accurately get actual material mechanical properties in the local region of structure,a micro-indentation test system incorporated by an electronic universal material test device has been established.An indenter displacement sensor and a group of special micro-indenter assemblies are estab-lished.A numerical indentation inversion analysis method by using ABAQUS software is also proposed in this study.Based on the above test system and analysis platform,an approach to obtaining material mechanical properties in the local region of structures is proposed and established.The ball indentation test is performed and combined with the energy method by using various changed mechanical properties of 316L austenitic stainless steel under differ-ent elongations.The investigated results indicate that the material mechanical properties and the micro-indentation morphological changes have evidently relevance.Compared with the tensile test results,the deviations of material mechanical parameters,such as hardness H,the hardening exponent n,the yield strength σy and others are within 5%obtained through the indentation test and the finite element analysis.It provides an effective and convenient method for obtaining the actual material mechanical properties in the local processing region of the structure.展开更多
A compact structured illumination chip based on integrated optics is proposed and fabricated on a silicon-on- insulator platform. Based on the simulation of Caussian beam interference, we adopt a chirped diffraction g...A compact structured illumination chip based on integrated optics is proposed and fabricated on a silicon-on- insulator platform. Based on the simulation of Caussian beam interference, we adopt a chirped diffraction grating to achieve a specific interference pattern. The experimental results match well with the simulations. The portability and flexibility of the structured illumination chip can be increased greatly through horizontal encapsulation. High levels of integration, compared with the conventional structured illumination approach, make this chip very compact, with a footprint of only around 1 mm2. The chip has no optical lenses and can be easily combined with a microfluidic system. These properties would make the chip very suitable for portable 3D scanner and compact super-resolution microscopy applications.展开更多
The finite element dynamic model for integrated structures containing distributed piezoelectric sensors and actuators ( S/As ) is formulated with a new piezoelectric plate bending element in this paper. The problem of...The finite element dynamic model for integrated structures containing distributed piezoelectric sensors and actuators ( S/As ) is formulated with a new piezoelectric plate bending element in this paper. The problem of active vibration control and suppression of integrated structures is investigated under constant gain negative velocity feedback control law. A general method for active vibration control and suppression of integrated structures is presented. Finally, numerical example is given to illustrate the validity of the method proposed in this paper.展开更多
As it is known, the closed inexact exterior form and associated closed dual form make up a differential-geometrical structure. Such a differential-geometrical structure describes a physical structure, namely, a pseudo...As it is known, the closed inexact exterior form and associated closed dual form make up a differential-geometrical structure. Such a differential-geometrical structure describes a physical structure, namely, a pseudostructure on which conservation laws are fulfilled (A closed dual form describes a pseudostructure. And a closed exterior form, as it is known, describes a conservative quantity, since the differential of closed form is equal to zero). It has been shown that closed inexact exterior forms, which describe physical structures, are obtained from the equations of mathematical physics. This process proceeds spontaneously under realization of any degrees of freedom of the material medium described. Such a process describes an emergence of physical structures and this is accompanied by an appearance of observed formations such as fluctuations, waves, turbulent pulsations and so on.展开更多
The unsatisfactory conductivity and large volume variation severely handicap the application of SnO_(2)in sodium-ion batteries(SIBs).Herein,we design unique three-layer structured SnO_(2)@C@TiO_(2)hollow spheres to ta...The unsatisfactory conductivity and large volume variation severely handicap the application of SnO_(2)in sodium-ion batteries(SIBs).Herein,we design unique three-layer structured SnO_(2)@C@TiO_(2)hollow spheres to tackle the above-mentioned issues.The hollow cavity affords empty space to accommodate the volume variation of SnO_(2),while the C and TiO_(2)protecting shells strengthen the structural integrity and enhances the electrical conductivity.As a result,the three-layer structured SnO_(2)@C@TiO_(2)hollow spheres demonstrate enhanced Na storage performances.The SnO_(2)@C@TiO_(2)manifests a reversible capacity two times to that of pristine SnO_(2)hollow spheres.In addition,Ex situ XRD reveals highly reversible alloying and conversion reactions in SnO_(2)@C@TiO_(2)hollow spheres.This study suggests the introduction of a hollow cavity and robust protecting shells is a promising strategy for constructing SIB anode materials.展开更多
In order to resolve the safety problem of the existing crane runway gir-ders(CRGs)with defects,the constraint-based R6 criterion is proposed to assess their structural integrity.The ex isting steel CRGs with defects a...In order to resolve the safety problem of the existing crane runway gir-ders(CRGs)with defects,the constraint-based R6 criterion is proposed to assess their structural integrity.The ex isting steel CRGs with defects at the weld joint between the upper flange and web plate,are characterized to three-dimensional finite element models with a semi-ellipse surface crack.The R6 criterion has been modified by considering the constraint effect which is represented by T-stress.The analysis results ilustrate that working condition of the cracked CRGs leads to high constraint level along the crack front.The crack aspect ratio(a/c)and run-way eccentricity(e)have significant influence on the integrity of the cracked CRGs.The integrity assessment results based on modified constraint-based R6 failure criterion enable to more effectively protect the cracked CRGs from brittle fracture failure.展开更多
The integrated optimal design of mechanical and control system is discussed in terms of the performance requirement and configuration for the single arm flexible manipulator. By combination of dynamics of flexible str...The integrated optimal design of mechanical and control system is discussed in terms of the performance requirement and configuration for the single arm flexible manipulator. By combination of dynamics of flexible structure and control theory, a PD feedback control system, which minimizes the settling time, has been designed. Then, the viable region of poles of the PD dosed-loop control system is decided according to overshoot and the settling time, and an integrated optimal model of structure and control of single arm manipulator is presented. Finally, the parameters of structure and control system are simultaneously optimized with respect to objective function induding the moment of inertia and the control effort of system.展开更多
文摘To detect space gravitational waves in the extremely low-frequency band,the telescope and optic-al platform require high stability and reliability.However,the cantilevered design presents challenges,espe-cially in the glass-metal hetero-bonding process.This study focuses on the analysis and experimental re-search of the bonding layer in the integrated structure.By optimizing the structural configuration and select-ing suitable bonding processes,the reliability of the telescope system is enhanced.The research indicates that using J-133 adhesive achieves the best performance,with a bonding layer thickness of 0.30 mm and a metal substrate surface roughness of Ra 0.8.These findings significantly enhance the reliability of the optical sys-tem while minimizing potential risks.
基金supported by the National Major Science and Technology Project,China(No.J2019-Ⅳ-0007-0075)the Fundamental Research Funds for the Central Universities,China(No.JKF-20240036)。
文摘To ensure the structural integrity of life-limiting component of aeroengines,Probabilistic Damage Tolerance(PDT)assessment is applied to evaluate the failure risk as required by airworthiness regulations and military standards.The PDT method holds the view that there exist defects such as machining scratches and service cracks in the tenon-groove structures of aeroengine disks.However,it is challenging to conduct PDT assessment due to the scarcity of effective Probability of Detection(POD)model and anomaly distribution model.Through a series of Nondestructive Testing(NDT)experiments,the POD model of real cracks in tenon-groove structures is constructed for the first time by employing the Transfer Function Method(TFM).A novel anomaly distribution model is derived through the utilization of the POD model,instead of using the infeasible field data accumulation method.Subsequently,a framework for calculating the Probability of Failure(POF)of the tenon-groove structures is established,and the aforementioned two models exert a significant influence on the results of POF.
基金financially supported by the earmarked fund for the earmarked fund for CARS(CARS-45)National Science Fund for Distinguished Young Scholars of China(32425056)+1 种基金the National Key R&D Program of China(2023YFD2400600)Sichuan Innovation Team of National Modern Agricultural Industry Technology System(SCCXTD-2024-16).
文摘Background Cetobacterium somerae,a symbiotic microorganism resident in various fish intestines,is recognized for its beneficial effects on fish gut health.However,the mechanisms underlying the effects of C.somerae on gut health remain unclear.In this experiment,we investigated the influence of C.somerae(CGMCC No.28843)on the growth performance,intestinal digestive and absorptive capacity,and intestinal structural integrity of juvenile grass carp(Ctenopharyngodon idella)and explored its potential mechanisms.Methods A cohort of 2,160 juvenile grass carp with an initial mean body weight of 11.30±0.01 g were randomly allocated into 6 treatment groups,each comprising 6 replicates(60 fish per replicate).The experimental diets were supplemented with C.somerae at graded levels of 0.00(control),0.68×10^(9),1.35×10^(9),2.04×10^(9),2.70×10^(9),and 3.40×10^(9)cells/kg feed.Following a 10-week experimental period,biological samples were collected for subsequent analyses.Results Dietary supplementation with C.somerae at 1.35×10^(9)cells/kg significantly enhanced growth performance,intestinal development,and nutrient retention rate in juvenile grass carp(P<0.05).The treatment resulted in increased intestinal acetic acid concentration and enhanced activities of digestive enzymes and brush border enzymes(P<0.05).Furthermore,it reduced intestinal permeability(P<0.05),preserved tight junctions(TJ)ultrastructural integrity,and increased the expression of TJ and adherens junctions(AJ)biomarkers at both protein and transcriptional levels(P<0.05).Mechanistically,these effects may be correlated with enhanced antioxidant capacity and coordinated modulation of the RhoA/ROCK,Sirt1,and PI3K/AKT signaling pathways.The appropriate supplementation levels,based on weight gain rate,feed conversion ratio,the activity of serum diamine oxidase and the content of lipopolysaccharide,were 1.27×10^(9),1.27×10^(9),1.34×10^(9)and 1.34×10^(9)cells/kg,respectively.Conclusions C.somerae improved intestinal digestive and absorptive capacity of juvenile grass carp,maintained intestinal structural integrity,and thus promoted their growth and development.This work demonstrates the potential of C.somerae as a probiotic for aquatic animals and provides a theoretical basis for its utilization in aquaculture.
基金This work was partly funded by the National Key R&D Project of China(2021YFB3400704)China State Railway Group(K2022J004 and N2023J011)China Railway Chengdu Group(CJ23018).
文摘Purpose–The safety and reliability of high-speed trains rely on the structural integrity of their components and the dynamic performance of the entire vehicle system.This paper aims to define and substantiate the assessment of the structural integrity and dynamical integrity of high-speed trains in both theory and practice.The key principles and approacheswill be proposed,and their applications to high-speed trains in Chinawill be presented.Design/methodology/approach–First,the structural integrity and dynamical integrity of high-speed trains are defined,and their relationship is introduced.Then,the principles for assessing the structural integrity of structural and dynamical components are presented and practical examples of gearboxes and dampers are provided.Finally,the principles and approaches for assessing the dynamical integrity of highspeed trains are presented and a novel operational assessment method is further presented.Findings–Vehicle system dynamics is the core of the proposed framework that provides the loads and vibrations on train components and the dynamic performance of the entire vehicle system.For assessing the structural integrity of structural components,an open-loop analysis considering both normal and abnormal vehicle conditions is needed.For assessing the structural integrity of dynamical components,a closed-loop analysis involving the influence of wear and degradation on vehicle system dynamics is needed.The analysis of vehicle system dynamics should follow the principles of complete objects,conditions and indices.Numerical,experimental and operational approaches should be combined to achieve effective assessments.Originality/value–The practical applications demonstrate that assessing the structural integrity and dynamical integrity of high-speed trains can support better control of critical defects,better lifespan management of train components and better maintenance decision-making for high-speed trains.
基金supported by the National Natural Science Foundation of China(Grant No.52105577)the Natural Science Foundation of Zhejiang Province(Grant Nos.LQ22E050001 and LQ21E080007)+1 种基金the Natural Science Foundation of Ningbo(Grant Nos.2021J088 and 2023J376)the Ningbo Yongjiang Talent Introduction Program(Grant No.2021A-137-G).
文摘The development of tissue engineering and regeneration research has created new platforms for bone transplantation.However,the preparation of scaffolds with good fiber integrity is challenging,because scaffolds prepared by traditional printing methods are prone to fiber cracking during solvent evaporation.Human skin has an excellent natural heat-management system,which helps to maintain a constant body temperature through perspiration or blood-vessel constriction.In this work,an electrohydrodynamic-jet 3D-printing method inspired by the thermal-management system of skin was developed.In this system,the evaporation of solvent in the printed fibers can be adjusted using the temperature-change rate of the substrate to prepare 3D structures with good structural integrity.To investigate the solvent evaporation and the interlayer bonding of the fibers,finite-element analysis simulations of a three-layer microscale structure were carried out.The results show that the solvent-evaporation path is from bottom to top,and the strain in the printed structure becomes smaller with a smaller temperaturechange rate.Experimental results verified the accuracy of these simulation results,and a variety of complex 3D structures with high aspect ratios were printed.Microscale cracks were reduced to the nanoscale by adjusting the temperature-change rate from 2.5 to 0.5℃s-1.Optimized process parameters were selected to prepare a tissue engineering scaffold with high integrity.It was confirmed that this printed scaffold had good biocompatibility and could be used for bone-tissue regeneration.This simple and flexible 3D-printing method can also help with the preparation of a wide range of micro-and nanostructured sensors and actuators.
基金funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan(Grant No.AP19680589).
文摘This research extends ongoing efforts to develop methods for reinforcing damaged main gas pipelines to prevent catastrophic failure.This study establishes the use of scaled-down experimental models for assessing the dynamic strength of damaged pipeline sections reinforced with wire wrapping or composite sleeves.A generalized dynamic model is introduced for numerical simulation to evaluate the effectiveness of reinforcement techniques.The model incorporates the elastoplastic behavior of pipe and wire materials,the influence of temperature on mechanical properties,the contact interaction between the pipe and the reinforcement components(including pretensioning),and local material failure under transient internal pressure.Based on these parameters,a finite element model was developed using ANSYS 19.2 to enable parametric studies.The accuracy of the proposed model was verified by comparing the simulation results with the experimental findings.Pipeline section samples containing non-penetrating longitudinal crackswere subjected to comparative analyses and transient pressure until critical failure.The unreinforced and steel wire-wrapped sections were investigated.The results confirm the feasibility of applying the computational model to study the dynamic strength of reinforced damaged pipe sections.Furthermore,pipelines with longitudinal cracks reinforced using circular composite overlays with orthotropic mechanical properties were examined,and recommendations are provided for selecting the geometric parameters of such overlays.
基金supported by the Research Program of Jilin Province Development and Reform Commission(2024C018-6).
文摘Oxygen vacancies(Ov)within metal oxide electrodes can enhance mass/charge transfer dynamics in energy storage systems.However,construction of surface Ovoften leads to instability in electrode structure and irreversible electrochemical reactions,posing a significant challenge.To overcome these challenges,atomic heterostructures are employed to address the structural instability and enhance the mass/charge transfer dynamics associated with phase conversion mechanism in aqueous electrodes,Herein,we introduce an atomic S-Bi_(2)O_(3)heterostructure(sulfur(S)anchoring on the surface Ovof Bi_(2)O_(3)).The integration of S within Bi_(2)O_(3)lattice matrix triggers a charge imbala nce at the heterointerfaces,ultimately resulting in the creation of a built-in electric field(BEF).Thus,the BEF attracts OH-ions to be adsorbed onto Bi within the regions of high electron cloud overlap in S-Bi_(2)O_(3),facilitating highly efficient charge transfer.Furthermore,the anchored S plays a pivotal role in preserving structural integrity,thus effectively stabilizing the phase conversion reaction of Bi_(2)O_(3).As a result,the S-Bi_(2)O_(3)electrode achieves72.3 mA h g^(-1)at 10 A g^(-1)as well as high-capacity retention of 81.9%after 1600 cycles.Our innovative SBi_(2)O_(3)design presents a groundbreaking approach for fabricating electrodes that exhibit efficient and stable mass and charge transfer capabilities.Furthermore,it enhances our understanding of the underlying reaction mechanism within energy storage electrodes.
文摘Ensuring the structural integrity of piping systems is crucial in industrial operations to prevent catastrophic failures and minimize shutdown time.This study investigates a transportation-damaged pipe exposed to high-temperature conditions and cyclic loading,representing a realistic challenge in plant operation.The objective was to evaluate the service life and integrity assessment parameters of the damaged pipe,subjected to 22,000 operational cycles under two daily charge and discharge conditions.The flaw size in the damaged pipe was determined based on a failure assessment procedure,ensuring a conservative and reliable input.The damage was characterized as a long axial surface crack with a depth of a=2 mm and half-length c=50 mm(c/a=25),a geometry not well covered by existing Stress Intensity Factor solutions.To address this limitation,a modified magnification factor(M*)was introduced and tested for the present damage case(c/a=25)and for additional crack geometries(c/a=28–70),which showed improved agreement with Finite Element Analysis(FEA)than Newman’s original formulation.Stress Intensity Factor and Plastic Limit Pressure,essential parameters for structural integrity assessment,were computed numerically using FEA and validated against analytical predictions.Fatigue crack growth was evaluated using the Paris law with crack propagation simulated numerically by Ansys’s S.M.A.R.T.The Failure Assessment Diagram(FAD)was used to assess service life,incorporating constant working pressure and fracture toughness while considering evolving crack size during propagation.Results showed that analytical predictions with the modified magnification factor matched FEA within 5%,while the original Newman formulation overestimated results.The analytical service life solution predicted approximately 8500 fewer cycles than the numerical,remaining conservative but efficient.These findings are based on the present case of a long axial surface crack with high aspect ratios(c/a=25–70,depending on crack depth),and while the modified magnification factor may also improve predictions for other geometries,this requires structured validation in future studies.
基金supported in part by the National Natural Science Foundation of China(Nos.61201048,61107063)the National Science and Technology Major Project(No.2017-VI-001-0094).
文摘To investigate the residual stress distribution and its influence on machining deformation in 6061-T651 aluminum alloy plates,this paper uses the crack compliance method to study the residual stress characteristics of 6061-T651 aluminum alloy plates with a thickness of 75 mm produced by two domestic manufacturers in China.The results indicate that both types of plates exhibit highly consistent and symmetrical M-shaped residual stress profile along the thickness direction,manifested as surface layer compression and core tension.The strain energy density across all specimens ranges from 1.27 kJ/m^(3)to 1.43 kJ/m^(3).Machining deformation simulations of an aerospace component incorporating these measured stresses showed minimal final deformation difference between the material sources,with a maximum deviation of only 0.009 mm across specimens.These findings provide critical data for material selection and deformation control in aerospace manufacturing.
基金National Natural Science Foundation of China.Grant ID:11872123.
文摘Projectiles made of reactive structure materials(RSM)can damage the target with not only kinetic but also chemical energy,but the enhanced damage potential of RSM may become compromised if extreme loading condition disintegrates the projectile before the target is reached.In this work,a ductile coating of Ni was introduced to a tungsten-zirconium(W-Zr)alloy,a typical brittle RSM,to preserve the damage potential of the projectile.Detonation driving tests were carried out with X-ray photography and gunpowder deflagration driving tests were carried out with high-speed photography for the coated and uncoated RSM samples,respectively.The craters on the witness target were analyzed by scanning electron microscopy and X-ray diffraction.The Ni coating was found to effectively preserve the damage potential of the W-Zr alloy under extreme loading conditions,whereas the uncoated sample fractured and ignited before impacting the target in both detonation and deflagration driving.The crack propagation between the reactively brittle core and the ductile coating was analyzed based on the crack arrest theory to mechanistically demonstrate how the coating improves the structural integrity and preserves the damage potential of the projectile.Specifically,the Ni coating envelops theW-Zr core until the coated sphere penetrates the target,and the coating is then eroded and worn to release the reactive core for the projectile to damage the target more intensively.
文摘The primary objective of the present literature review is to provide a constructive and systematical discussion based on the relevant development,unsolved issues,gaps,and misconceptions in the literature regarding the fields of study that are building blocks of artificial intelligence-aided life extension assessment for offshore wind turbine support structures.The present review aims to set up the needed guidelines to develop a multi-disciplinary framework for life extension management and certification of the support structures for offshore wind turbines using artificial intelligence.The main focus of the literature review centres around the intelligent risk-based life extension management of offshore wind turbine support structures.In this regard,big data analytics,advanced signal processing techniques,supervised and unsupervised machine learning methods are discussed within the structural health monitoring and condition-based maintenance planning,the development of digital twins.Furthermore,the present review discusses the critical failure mechanisms affecting the structural condition,such as high-cycle fatigue,low-cycle fatigue,fracture,ultimate strength,and corrosion,considering deterministic and probabilistic approaches.
文摘A-Jacks are concrete armor units that are used in both open channel and coastal applications.In open channel applications,they are used for bank and toe protection,flow and grade control,bridge pier scour protection,energy dissipation,and habitat.These small units may be fabricated in standard block machines.In coastal applications,A-Jacks are used in breakwaters,jetties,revetments,and habitat development.Coastal units are generally much larger and more robust than the small open channel units.This paper focuses on coastal applications and in particular,combines results on three topics:(1)recent hydraulic model studies,(2)alternative fabrication methods,and(3)bundle placement construction methods.Hydraulic models studies were conducted that examined the standard random and uniform placement methods,and also the bundle placement method.In bundle placement,3~20 A-Jacks are banded together,lifted with a spreader bar,and placed as a single crane pick.This significantly decreases installation time during construction.It also provides a more hydraulically stable placement technique.The hydraulic model tests examined the bundle stability in random waves for cases where the binding remains in tack and is removed.The geometry of A-Jacks enables a variety of fabrication techniques.One option is to fabricate the A-Jacks as two pieces using flat forms and then grout the two pieces together.Flat forms may be used in conventional block machines for A-Jacks sizes up to 1.3 m.Larger sizes may be wet cast in flat forms or gang forms.The A-Jacks geometry has been recently modified to increase grouting efficient and strength.Large A- Jacks may also be cast in a single piece using 'clam shell' type forms.
基金financially supported by the National Natural Science Foundation of China(51532009)Science and Technology Commission of Shanghai Municipality(16DZ2260603,18ZR1401400)+1 种基金Shanghai Technical Platform for Testing and Characterization on Inorganic Materials(19DZ2290700)Loughborough University’s PhD studentship provided to SR。
文摘Ultra-high temperature ceramics have been considered as good candidates for plasma facing materials due to their combination of high melting point,high strength and hardness,high thermal conductivity as well as good chemical inertness.In this study,zirconium diboride has been chosen to investigate its irradiation damage behavior.Irradiated by 4 MeV Au^(2+)with a total fluence of 2.5×10^(16)cm^(-2),zirconium diboride ceramic shows substantial resilience to irradiation-induced damage with its structural integrity well maintained but mild damage at lattice level.Grazing incident X-ray diffraction evidences no change of the hexagonal structure in the irradiated region but its lattice parameter a increased and c decreased,giving a volume shrinkage of 0.46%.Density functional theory calculation shows that such lattice shrinkage corresponds to a non-stoichiometric compound as ZrB1.97.Electron energy-loss spectroscopy in a transmission electron microscope revealed an increase of valence electrons in zirconium,suggesting boron vacancies were indeed developed by the irradiation.Alo ng the irradiation depth,long dislocations were observed inside top layer with a depth of 750 nm where the implanted Au ions reached the peak concentration.Underneath the top layer,a high density of Frank dislocations is formed by the cascade collision down to a depth of 1150 nm.All the features show the potential of ZrB_(2) to be used as structural material in nuclear system.
基金Supported by National Natural Science Foundation of China(Grant No.52075434)Key R&D Projects in Shaanxi Province(Grant No.2021KW-36).
文摘The hot or cold processing would induce the change and the inhomogeneous of the material mechanical properties in the local processing region of the structure,and it is difficult to obtain the specific mechanical properties in these regions by using the traditional material tensile test.To accurately get actual material mechanical properties in the local region of structure,a micro-indentation test system incorporated by an electronic universal material test device has been established.An indenter displacement sensor and a group of special micro-indenter assemblies are estab-lished.A numerical indentation inversion analysis method by using ABAQUS software is also proposed in this study.Based on the above test system and analysis platform,an approach to obtaining material mechanical properties in the local region of structures is proposed and established.The ball indentation test is performed and combined with the energy method by using various changed mechanical properties of 316L austenitic stainless steel under differ-ent elongations.The investigated results indicate that the material mechanical properties and the micro-indentation morphological changes have evidently relevance.Compared with the tensile test results,the deviations of material mechanical parameters,such as hardness H,the hardening exponent n,the yield strength σy and others are within 5%obtained through the indentation test and the finite element analysis.It provides an effective and convenient method for obtaining the actual material mechanical properties in the local processing region of the structure.
基金Supported by the National Natural Science Foundation of China under Grant No 61334008the National High-Technology Research and Development Program of China under Grant No 2015AA016904the Instrument Developing Project of the Chinese Academy of Sciences under Grant No YZ201301
文摘A compact structured illumination chip based on integrated optics is proposed and fabricated on a silicon-on- insulator platform. Based on the simulation of Caussian beam interference, we adopt a chirped diffraction grating to achieve a specific interference pattern. The experimental results match well with the simulations. The portability and flexibility of the structured illumination chip can be increased greatly through horizontal encapsulation. High levels of integration, compared with the conventional structured illumination approach, make this chip very compact, with a footprint of only around 1 mm2. The chip has no optical lenses and can be easily combined with a microfluidic system. These properties would make the chip very suitable for portable 3D scanner and compact super-resolution microscopy applications.
文摘The finite element dynamic model for integrated structures containing distributed piezoelectric sensors and actuators ( S/As ) is formulated with a new piezoelectric plate bending element in this paper. The problem of active vibration control and suppression of integrated structures is investigated under constant gain negative velocity feedback control law. A general method for active vibration control and suppression of integrated structures is presented. Finally, numerical example is given to illustrate the validity of the method proposed in this paper.
文摘As it is known, the closed inexact exterior form and associated closed dual form make up a differential-geometrical structure. Such a differential-geometrical structure describes a physical structure, namely, a pseudostructure on which conservation laws are fulfilled (A closed dual form describes a pseudostructure. And a closed exterior form, as it is known, describes a conservative quantity, since the differential of closed form is equal to zero). It has been shown that closed inexact exterior forms, which describe physical structures, are obtained from the equations of mathematical physics. This process proceeds spontaneously under realization of any degrees of freedom of the material medium described. Such a process describes an emergence of physical structures and this is accompanied by an appearance of observed formations such as fluctuations, waves, turbulent pulsations and so on.
基金financially supported by Shenzhen Fundamental Research Program(JCYJ20190809114409397)
文摘The unsatisfactory conductivity and large volume variation severely handicap the application of SnO_(2)in sodium-ion batteries(SIBs).Herein,we design unique three-layer structured SnO_(2)@C@TiO_(2)hollow spheres to tackle the above-mentioned issues.The hollow cavity affords empty space to accommodate the volume variation of SnO_(2),while the C and TiO_(2)protecting shells strengthen the structural integrity and enhances the electrical conductivity.As a result,the three-layer structured SnO_(2)@C@TiO_(2)hollow spheres demonstrate enhanced Na storage performances.The SnO_(2)@C@TiO_(2)manifests a reversible capacity two times to that of pristine SnO_(2)hollow spheres.In addition,Ex situ XRD reveals highly reversible alloying and conversion reactions in SnO_(2)@C@TiO_(2)hollow spheres.This study suggests the introduction of a hollow cavity and robust protecting shells is a promising strategy for constructing SIB anode materials.
基金The works described in this paper are financially supported by the National Program on Key Research Project(2016YFC0701301-02),to which the authors are most grateful.
文摘In order to resolve the safety problem of the existing crane runway gir-ders(CRGs)with defects,the constraint-based R6 criterion is proposed to assess their structural integrity.The ex isting steel CRGs with defects at the weld joint between the upper flange and web plate,are characterized to three-dimensional finite element models with a semi-ellipse surface crack.The R6 criterion has been modified by considering the constraint effect which is represented by T-stress.The analysis results ilustrate that working condition of the cracked CRGs leads to high constraint level along the crack front.The crack aspect ratio(a/c)and run-way eccentricity(e)have significant influence on the integrity of the cracked CRGs.The integrity assessment results based on modified constraint-based R6 failure criterion enable to more effectively protect the cracked CRGs from brittle fracture failure.
文摘The integrated optimal design of mechanical and control system is discussed in terms of the performance requirement and configuration for the single arm flexible manipulator. By combination of dynamics of flexible structure and control theory, a PD feedback control system, which minimizes the settling time, has been designed. Then, the viable region of poles of the PD dosed-loop control system is decided according to overshoot and the settling time, and an integrated optimal model of structure and control of single arm manipulator is presented. Finally, the parameters of structure and control system are simultaneously optimized with respect to objective function induding the moment of inertia and the control effort of system.
