Concrete is one of the most important elements in building construction.However,concrete used in construction is susceptible to damage due to corrosion.The influence of corrosive substances causes changes in the reinf...Concrete is one of the most important elements in building construction.However,concrete used in construction is susceptible to damage due to corrosion.The influence of corrosive substances causes changes in the reinforcing steel and affects the strength of the structure.The repair method is one approach to overcome this problem.This research aims to determine the effect of grouting and jacketing repairs on corroded concrete.The concrete used has dimensions of 15 cm×15 cm×60 cm with planned corrosion variations of 50%,60%,and 70%.The test objects were tested using the Non-Destructive Testing(NDT)method using Ultrasonic Pulse Velocity(UPV).The test results show that the average speed of normal concrete is 5070 m/s,while the lowest average speed is 3070 m/s on the 70%planned corrosion test object.The test object was then given a load of 1600 kgf.At this stage,there is a decrease in speed and wave shape with the lowest average speed obtained at 2753 m/s.The repair method is an effort to restore concrete performance by using grouting and jacketing.Grouting is done by injecting mortar material into it.Jacketing involves adding thickness to the existing concrete layer with additional layers of concrete.After improvements were made,there was an improvement in the UPV test,with a peak speed value of 4910 m/s.Repairing concrete by filling cracks can improve concrete continuity and reduce waveform distortion,thereby increasing wave propagation speed.展开更多
The Northridge earthquake inflicted various levels of damage upon a large number of Caltrans' bridges not retrofitted by column jacketing.In this respect,this study represents results of fragility curve developmen...The Northridge earthquake inflicted various levels of damage upon a large number of Caltrans' bridges not retrofitted by column jacketing.In this respect,this study represents results of fragility curve development for two (2) sample bridges typical in southern California,strengthened for seismic retrofit by means of steel jacketing of bridge columns.Monte Carlo simulation is performed to study nonlinear dynamic responses of the bridges before and after column retrofit.Fragility curves in this study are represented by lognormal distribution functions with two parameters and developed as a function of PGA.The sixty (60) ground acceleration time histories for the Los Angeles area developed for the Federal Emergency Management Agency (FEMA) SAC (SEAOC-ATC CUREe) steel project are used for the dynamic analysis of the bridges. The improvement in the fragility with steel jacketing is quantified by comparing fragility curves of the bridge before and after column retrofit.In this first attempt to formulate the problem of fragility enhancement,the quantification is made by comparing the median values of the fragility curves before and after the retrofit.Under the hypothesis that this quantification also applies to empirical fragility curves developed on the basis of Northridge earthquake damage,the enhanced version of the empirical curves is developed for the ensuing analysis to determine the enhancement of transportation network performance due to the retrofit.展开更多
A cable-in-conduit conductor(CICC ) production line was designed and constructed in Institute of Plasma Physics of Chinese Academy of Sciences (IPPCAS) by the end of 2000. It can produce a length of 600 meters and thr...A cable-in-conduit conductor(CICC ) production line was designed and constructed in Institute of Plasma Physics of Chinese Academy of Sciences (IPPCAS) by the end of 2000. It can produce a length of 600 meters and three kinds of sections of 20.8±0. 1×20.8±0.1, 20.4±0. 1×20.4± 0.1 and 18.6±0.1×18.6±0.1mm2. If the rollers of the shaping machine are changed, it can also produce other sizes of CICCs. So-called inserting-cable technology is adopted in this production line, where the procedures consist of tube pre-treatment (cleaning, pressure and leakage testing, end cutting), conduits butt-welding, six kinds of quality checking (endoscopy, dye penetration, pressure control, leakage testing, ultrasonic inspection and X-ray testing), cable inserting, shaping (compacting & squaring), pre-bending & winding and final checking. Now all the instruments and facilities required for these technologies have been installed and got ready. Some key technologies have been explored and good results obtained. Some short samples were produced and a 600 meters long sample was made out in August, 2001.展开更多
Dear Li Mingchao,How are you?I miss you very much.Many thanks for the leather jacket!I really love it.Green is my favorite color!You kept it in mind!It's just my size.Every time I wear it,I think of you.I'm fi...Dear Li Mingchao,How are you?I miss you very much.Many thanks for the leather jacket!I really love it.Green is my favorite color!You kept it in mind!It's just my size.Every time I wear it,I think of you.I'm fine here in Hong Kong.Last week I had a birthday party.展开更多
1 In a town of fewer than 1,000 people,it can be hard to keep a secret.And yet no one in McBride,a mountain community in British Columbia,can figure out how a local deer came to be wearing a reflective jacket or why t...1 In a town of fewer than 1,000 people,it can be hard to keep a secret.And yet no one in McBride,a mountain community in British Columbia,can figure out how a local deer came to be wearing a reflective jacket or why the deer has been so hard to track down.展开更多
The novel structural reliability methodology presented in this study is especially well suited for multidimensional structural dynamics that are physically measured or numerically simulated over a representative timel...The novel structural reliability methodology presented in this study is especially well suited for multidimensional structural dynamics that are physically measured or numerically simulated over a representative timelapse.The Gaidai multivariate reliability method is applied to an operational offshore Jacket platform that operates in Bohai Bay.This study demonstrates the feasibility of this method to accurately estimate collapse risks in dynamic systems under in situ environmental stressors.Modern reliability approaches do not cope easily with the high dimensionality of real engineering dynamic systems,as well as nonlinear intercorrelations between various structural components.The Jacket offshore platform is chosen as the case study for this reliability analysis because of the presence of various hotspot stresses that synchronously arise in its structural parts.The authors provide a straightforward,precise method for estimating overall risks of operational failure,damage,or hazard for nonlinear multidimensional dynamic systems.The latter tool is important for offshore engineers during the design stage.展开更多
As an important part of offshore wind turbine support and fixed units, the multibucket jacket foundation bears large loads and a complex marine environment. In this paper, the horizontal bearing characteristics of the...As an important part of offshore wind turbine support and fixed units, the multibucket jacket foundation bears large loads and a complex marine environment. In this paper, the horizontal bearing characteristics of the four-bucket jacket foundation of offshore wind power in sandy soil are studied. Through model tests and numerical simulations, the influence of bucket foundation sealing properties, load application speed, and loading direction on foundation-bearing capacity are discussed. The results show that the horizontal ultimate bearing capacity of the foundation in the nonsealing condition is decreased by 51.3% compared with the sealing condition;therefore, after the foundation penetration construction is completed, the bucket sealing must be ensured to increase the load-bearing performance of the structure. At a loading speed of 3.25 mm/s, the horizontal ultimate bearing capacity of the foundation is increased by 9.4% over the working condition of 1.85 mm/s. The bearing capacity of the foundation is maximized in the loading direction α =45° and is the smallest when α =0°. That is, the foundation can maximize its loadbearing performance under the condition of single-bucket compression/tension. During the design process, the main load of the structure should be loaded in the 45° direction. The contrast error of the experiment and numerical simulation does not exceed 10%. The research results have important guiding importance for designing and constructing the jacket foundation and can be used as a reference for the stable operation and sustainable development of offshore wind power systems.展开更多
Have we ever seen such a shocking garment in the fashion industry?A down jacket that claims to be one but uses absolutely no down,yet possesses remarkable heating and insulating properties,all designed with a colorles...Have we ever seen such a shocking garment in the fashion industry?A down jacket that claims to be one but uses absolutely no down,yet possesses remarkable heating and insulating properties,all designed with a colorless aesthetic.It resembles clothing that has come from the future.The secret behind this captivating design lies in"SOLAMENTR■"developed by Sumitomo Metal Mining Co.,Ltd.展开更多
Outdoor jackets are engineered to protect against extreme weather while ensuring comfort and safety. Key to this protection is the thermal properties, achieved through insulation materials like down feathers and synth...Outdoor jackets are engineered to protect against extreme weather while ensuring comfort and safety. Key to this protection is the thermal properties, achieved through insulation materials like down feathers and synthetic fibers, which trap heat and minimize heat loss. Resistance to wind, rain, and snow is provided by waterproof and windproof fabrics, while breathability allows moisture to escape, maintaining a comfortable microclimate. Air permeability and water resistance are essential for achieving this balance. This study examines two outdoor jacket prototypes with six material layers each. The outer layer (Layer 1) consists of 100% polyester coated with polyurethane for waterproofing. Inner layers (Layers 2, 3, and 6) use wool/cotton and wool/polyamide blends, offering insulation and moisture-wicking properties. Down feathers are used as the filling material, providing excellent warmth. Advanced materials like graphene and silver honeycomb fabrics were included to enhance thermal conductivity and regulate heat transfer. Performance testing focused on thermal conductivity, comfort (water and air permeability), and mechanical properties like tensile strength and tear resistance. Tests also assessed spray application and fastness to evaluate durability under environmental exposure. Results showed that jackets with silver-infused honeycomb fabrics had superior thermal conductivity, enabling better heat regulation and comfort in harsh conditions. The findings highlight the advantages of integrating silver honeycomb fabrics into outdoor jackets. These materials enhance insulation, thermal regulation, and overall comfort, making them ideal for high-performance designs. Incorporating such fabrics ensures functionality, durability, and user protection in extreme environments.展开更多
Jacket platforms constitute the foundational infrastructure of offshore oil and gas field exploitation.How to efficiently and accurately monitor the mechanical properties of jacket structures is one of the key problem...Jacket platforms constitute the foundational infrastructure of offshore oil and gas field exploitation.How to efficiently and accurately monitor the mechanical properties of jacket structures is one of the key problems to be solved to ensure the safe operation of the platform.To address the practical engineering problem that it is difficult to monitor the stress response of the tubular joints of jacket platforms online,a digital twin reduced-order method for real-time prediction of the stress response of tubular joints is proposed.In the offline construction phase,multi-scale modeling and multi-parameter experimental design methods are used to obtain the stress response data set of the jacket structure.Proper orthogonal decomposition is employed to extract the main feature information from the snapshot matrix,resulting in a reduced-order basis.The leave-one-out cross-validation method is used to select the optimal modal order for constructing the reduced-order model(ROM).In the online prediction phase,a digital twin model of the tubular joint is established,and the prediction performance of the ROM is analyzed and verified through using random environmental load and field environmental monitoring data.The results indicate that,compared with traditional numerical simulations of tubular joints,the ROM based on the proposed reduced-order method is more efficient in predicting the stress response of tubular joints while ensuring accuracy and robustness.展开更多
The jacket structure and transition piece comprise the supporting structure of a bottom-fixed offshore wind turbine(OWT)connected to the steel tower,which determines the overall structural dynamic performance of the e...The jacket structure and transition piece comprise the supporting structure of a bottom-fixed offshore wind turbine(OWT)connected to the steel tower,which determines the overall structural dynamic performance of the entire OWT.Ideally,optimal performance can be realized by effectively coordinating two components,notwithstanding their separate design processes.In pursuit of this objective,this paper proposes a concurrent design methodology for the jacket structure and transition piece by exploiting topology optimization(TO).The TO for a three-legged jacket foundation is formulated by minimizing static compliance.In contrast to conventional TO,two separated volume fractions are imposed upon the structural design domain of the jacket structure and transition piece to ensure continuity.A 5 MW(megawatt)OWT supported by a four-legged or three-legged jacket substructure is under investigation.The external loads are derived from various design load cases that are acquired using the commercial software platform DNV Bladed(Det Norske Veritas).Through a comparative analysis of the fundamental frequency and maximum nodal deformation,it was found that the optimized solution demonstrates a reduced weight and superior stiffness.The findings demonstrate the present concurrent design approach using TO can yield significant benefits by reducing the overall design cycle and enhancing the feasibility of the final design.展开更多
On the stage of China Media Group’s 2025 Spring Festival Gala,more than a dozen humanoid robots dressed in floral padded jackets danced alongside human counterparts in a creative folk dance performance.The robots not...On the stage of China Media Group’s 2025 Spring Festival Gala,more than a dozen humanoid robots dressed in floral padded jackets danced alongside human counterparts in a creative folk dance performance.The robots not only smoothly twisted their waists and mimicked human leg-kicking movements,but also spun handkerchiefs,displaying extremely dexterous moves and exceptional skills.展开更多
Compared with PELE with inert fillings such as polyethylene and nylon,reactive PELE(RPELE)shows excellent damage effects when impacting concrete targets due to the filling deflagration reaction.In present work,an anal...Compared with PELE with inert fillings such as polyethylene and nylon,reactive PELE(RPELE)shows excellent damage effects when impacting concrete targets due to the filling deflagration reaction.In present work,an analytical model describing the jacket deformation and concrete target damage impacted by RPELE was presented,in which the radial rarefaction and filling deflagration reaction were considered.The impact tests of RPELE on concrete target in the 592-1012 m/s were carried out to verify the analytical model.Based on the analytical model,the angle-length evolution mechanism of the jacket bending-curling deformation was revealed,and the concrete target damage was further analyzed.One can find out that the average prediction errors of the front crater,opening and back crater are 6.8%,8.5%and 7.1%,respectively.Moreover,the effects of radial rarefaction and deflagration were discussed.It was found that the neglect of radial rarefaction overestimates the jacket deformation and concrete target damage,while the deflagration reaction of filling increases the diameter of the front crater,opening and back crater by 25.4%,24.3%and 31.1%,respectively.The research provides a valuable reference for understanding and predicting the jacket deformation and concrete target damage impacted by RPELE.展开更多
The tripod foundation(TF)is a prevalent foundation configuration in contemporary engineering practices.In comparison to a single pile,TF comprised interconnected individual piles,resulting in enhanced bearing capacity...The tripod foundation(TF)is a prevalent foundation configuration in contemporary engineering practices.In comparison to a single pile,TF comprised interconnected individual piles,resulting in enhanced bearing capacity and stability.A physical model test was conducted within a sandy soil foundation,systematically varying the length-to-diameter ratio of the TF.The investigation aimed to comprehend the impact of altering the height of the central bucket on the historical horizontal bearing capacity of the foundation in saturated sand.Additionally,the study scrutinized the historical consequences of soil pressure and pore water pressure surrounding the bucket throughout the loading process.The historical findings revealed a significant enhancement in the horizontal bearing capacity of the TF under undrained conditions.When subjected to a historical horizontal loading angle of 0°for a single pile,the multi-bucket foundation exhibited superior historical bearing capacity compared to a single-pile foundation experiencing a historical loading angle of 180°under pulling conditions.With each historical increment in bucket height from 150 mm to 350 mm in 100 mm intervals,the historical horizontal bearing capacity of the TF exhibited an approximately 75%increase relative to the 150 mm bucket height,indicating a proportional relationship.Importantly,the historical internal pore water pressure within the bucket foundation remained unaffected by drainage conditions during loading.Conversely,undrained conditions led to a historical elevation in pore water pressure at the lower side of the pressure bucket.Consequently,in practical engineering applications,the optimization of the historical bearing efficacy of the TF necessitated the historical closure of the valve atop the foundation to sustain internal negative pressure within the bucket.This historical measure served to augment the historical horizontal bearing capacity.Simultaneously,historical external loads,such as wind,waves,and currents,were directed towards any individual bucket within the TF for optimal historical performance.展开更多
The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position ...The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position on the suppression effect.In this work,the wind-vortex-induced vibration of an elastic pipe of a deepwater jacket was studied,and vibrations were suppressed by using an NES.A van der Pol wake oscillator was used to simulate vortex-induced force,and the dynamic equation of the pipe considering the NES was established.The Galerkin method was applied to discretize the motion equation,and the vortex-induced vibration(VIV)of the pipe at reduced wind speeds was numerically analyzed.The novelty of this research is that particle swarm optimization was used to optimize the parameters of the NES to improve vibration suppression.The influence of the installation position,nonlinear stiffness,and damping parameters of the NES on vibration suppression was analyzed.Results showed that the optimized parameter combinations of the NES can effectively reduce wind-vortex-induced pipe vibration.The installation position of the NES had a significant effect on vibration suppression,and the midpoint of the pipe was the optimal NES installation position.An increase in stiffness or a 10% decrease in damping may cause vibration suppression failure.The results of this study provide some guidance for VIV suppression in deepwater jacket pipes.展开更多
The evolution of threats and scenarios requires continuous performance improvements of ballistic protections for armed forces.From a modeling point of view,it is necessary to use sufficiently precise material behavior...The evolution of threats and scenarios requires continuous performance improvements of ballistic protections for armed forces.From a modeling point of view,it is necessary to use sufficiently precise material behavior models to accurately describe the phenomena observed during the impact of a projectile on a protective equipment.In this context,the goal of this paper is to characterize the behavior of a small caliber steel jacket by combining experimental and numerical approaches.The experimental method is based on the lateral compression of ring specimens directly machined from the thin and small ammunition.Various speeds and temperatures are considered in a quasi-static regime in order to reveal the strain rate and temperature dependencies of the tested material.The Finite Element Updating Method(FEMU)is used.Experimental results are coupled with an inverse optimization method and a finite element numerical model in order to determine the parameters of a constitutive model representative of the jacket material.Predictions of the present model are verified against experimental results and a parametric study as well as a discussion on the identified material parameters are proposed.The results indicate that the strain hardening parameter can be neglected and the behavior of the thin steel jacket can be described by a modeling without strain hardening sensitivity.展开更多
Columbia is a world-renowned manufacturer of outdoor products.Its product range covers all aspects of outdoor equipment such as jackets,down jackets,outdoor footwear,backpacks and accessories.In the outdoor industry,C...Columbia is a world-renowned manufacturer of outdoor products.Its product range covers all aspects of outdoor equipment such as jackets,down jackets,outdoor footwear,backpacks and accessories.In the outdoor industry,Columbia was the first brand to propose a three-in-one garment design concept.This practical design has since been adopted by almost every outdoor brand.The Columbia Jacket is positioned for urban outdoor recreation.Its rugged materials and design make it suitable for low-altitude outdoor sports as well as urban commuting.展开更多
When the gentle breeze of spring starts to fill the air,it's often a time of transition,where the chill of winter gives way to the warmth of the coming season.However,for those who love the outdoors,spring can sti...When the gentle breeze of spring starts to fill the air,it's often a time of transition,where the chill of winter gives way to the warmth of the coming season.However,for those who love the outdoors,spring can still present its own set of challenges,especially when it's time to choose the right jacket.Whether you're hiking in the hills,exploring the trails,or just taking a leisurely walk in the park,having a jacket that offers the perfect blend of warmth,comfort,and breathability is crucial.We'll delve into the various options available for jackets that are perfect for the outdoors in spring.展开更多
Arc’teryx’s Beta AR Jacket sets a new bar in terms of what a mainstream outdoor jacket can do.You’ll turn around and charge headfirst into a rainstorm with this fully impermeable outer layer that packs in everythin...Arc’teryx’s Beta AR Jacket sets a new bar in terms of what a mainstream outdoor jacket can do.You’ll turn around and charge headfirst into a rainstorm with this fully impermeable outer layer that packs in everything you need to lock in your core and stay dry.Unlike some jackets,the best part is that this jacket also pays dividends in sunny weather.While it’s designed for nasty weather,it stays comfortable when the storm passes away.The company’s high-tech waterproof membrane simultaneously wicks moisture and finally kicks that classic clammy raincoat feeling to the curb.展开更多
In many cases, seismic appraisal of existing structures is carried out by the two step method and seismic strengthening of R.C. frame structures is solved just based on rough calculation or experience of designers, wh...In many cases, seismic appraisal of existing structures is carried out by the two step method and seismic strengthening of R.C. frame structures is solved just based on rough calculation or experience of designers, which may lead to either lack of safety or too conservative in design. According to some related criteria and experts experience, a computer program is developed specially for seismic appraisal and seismic strengthening of R.C. frames (not more than 10 storeys) in this paper. Because the progra...展开更多
基金supported by the Ministry of Education,Culture,Research,and Technology(Indonesia),Grant number 107/E5/PG.02.00.PL/2024,AZ.
文摘Concrete is one of the most important elements in building construction.However,concrete used in construction is susceptible to damage due to corrosion.The influence of corrosive substances causes changes in the reinforcing steel and affects the strength of the structure.The repair method is one approach to overcome this problem.This research aims to determine the effect of grouting and jacketing repairs on corroded concrete.The concrete used has dimensions of 15 cm×15 cm×60 cm with planned corrosion variations of 50%,60%,and 70%.The test objects were tested using the Non-Destructive Testing(NDT)method using Ultrasonic Pulse Velocity(UPV).The test results show that the average speed of normal concrete is 5070 m/s,while the lowest average speed is 3070 m/s on the 70%planned corrosion test object.The test object was then given a load of 1600 kgf.At this stage,there is a decrease in speed and wave shape with the lowest average speed obtained at 2753 m/s.The repair method is an effort to restore concrete performance by using grouting and jacketing.Grouting is done by injecting mortar material into it.Jacketing involves adding thickness to the existing concrete layer with additional layers of concrete.After improvements were made,there was an improvement in the UPV test,with a peak speed value of 4910 m/s.Repairing concrete by filling cracks can improve concrete continuity and reduce waveform distortion,thereby increasing wave propagation speed.
基金MCEER/FHWA under Contract No.DTFH 61-98-C-00094Caltrans under Contract No.59A0304
文摘The Northridge earthquake inflicted various levels of damage upon a large number of Caltrans' bridges not retrofitted by column jacketing.In this respect,this study represents results of fragility curve development for two (2) sample bridges typical in southern California,strengthened for seismic retrofit by means of steel jacketing of bridge columns.Monte Carlo simulation is performed to study nonlinear dynamic responses of the bridges before and after column retrofit.Fragility curves in this study are represented by lognormal distribution functions with two parameters and developed as a function of PGA.The sixty (60) ground acceleration time histories for the Los Angeles area developed for the Federal Emergency Management Agency (FEMA) SAC (SEAOC-ATC CUREe) steel project are used for the dynamic analysis of the bridges. The improvement in the fragility with steel jacketing is quantified by comparing fragility curves of the bridge before and after column retrofit.In this first attempt to formulate the problem of fragility enhancement,the quantification is made by comparing the median values of the fragility curves before and after the retrofit.Under the hypothesis that this quantification also applies to empirical fragility curves developed on the basis of Northridge earthquake damage,the enhanced version of the empirical curves is developed for the ensuing analysis to determine the enhancement of transportation network performance due to the retrofit.
文摘A cable-in-conduit conductor(CICC ) production line was designed and constructed in Institute of Plasma Physics of Chinese Academy of Sciences (IPPCAS) by the end of 2000. It can produce a length of 600 meters and three kinds of sections of 20.8±0. 1×20.8±0.1, 20.4±0. 1×20.4± 0.1 and 18.6±0.1×18.6±0.1mm2. If the rollers of the shaping machine are changed, it can also produce other sizes of CICCs. So-called inserting-cable technology is adopted in this production line, where the procedures consist of tube pre-treatment (cleaning, pressure and leakage testing, end cutting), conduits butt-welding, six kinds of quality checking (endoscopy, dye penetration, pressure control, leakage testing, ultrasonic inspection and X-ray testing), cable inserting, shaping (compacting & squaring), pre-bending & winding and final checking. Now all the instruments and facilities required for these technologies have been installed and got ready. Some key technologies have been explored and good results obtained. Some short samples were produced and a 600 meters long sample was made out in August, 2001.
文摘Dear Li Mingchao,How are you?I miss you very much.Many thanks for the leather jacket!I really love it.Green is my favorite color!You kept it in mind!It's just my size.Every time I wear it,I think of you.I'm fine here in Hong Kong.Last week I had a birthday party.
文摘1 In a town of fewer than 1,000 people,it can be hard to keep a secret.And yet no one in McBride,a mountain community in British Columbia,can figure out how a local deer came to be wearing a reflective jacket or why the deer has been so hard to track down.
文摘The novel structural reliability methodology presented in this study is especially well suited for multidimensional structural dynamics that are physically measured or numerically simulated over a representative timelapse.The Gaidai multivariate reliability method is applied to an operational offshore Jacket platform that operates in Bohai Bay.This study demonstrates the feasibility of this method to accurately estimate collapse risks in dynamic systems under in situ environmental stressors.Modern reliability approaches do not cope easily with the high dimensionality of real engineering dynamic systems,as well as nonlinear intercorrelations between various structural components.The Jacket offshore platform is chosen as the case study for this reliability analysis because of the presence of various hotspot stresses that synchronously arise in its structural parts.The authors provide a straightforward,precise method for estimating overall risks of operational failure,damage,or hazard for nonlinear multidimensional dynamic systems.The latter tool is important for offshore engineers during the design stage.
文摘As an important part of offshore wind turbine support and fixed units, the multibucket jacket foundation bears large loads and a complex marine environment. In this paper, the horizontal bearing characteristics of the four-bucket jacket foundation of offshore wind power in sandy soil are studied. Through model tests and numerical simulations, the influence of bucket foundation sealing properties, load application speed, and loading direction on foundation-bearing capacity are discussed. The results show that the horizontal ultimate bearing capacity of the foundation in the nonsealing condition is decreased by 51.3% compared with the sealing condition;therefore, after the foundation penetration construction is completed, the bucket sealing must be ensured to increase the load-bearing performance of the structure. At a loading speed of 3.25 mm/s, the horizontal ultimate bearing capacity of the foundation is increased by 9.4% over the working condition of 1.85 mm/s. The bearing capacity of the foundation is maximized in the loading direction α =45° and is the smallest when α =0°. That is, the foundation can maximize its loadbearing performance under the condition of single-bucket compression/tension. During the design process, the main load of the structure should be loaded in the 45° direction. The contrast error of the experiment and numerical simulation does not exceed 10%. The research results have important guiding importance for designing and constructing the jacket foundation and can be used as a reference for the stable operation and sustainable development of offshore wind power systems.
文摘Have we ever seen such a shocking garment in the fashion industry?A down jacket that claims to be one but uses absolutely no down,yet possesses remarkable heating and insulating properties,all designed with a colorless aesthetic.It resembles clothing that has come from the future.The secret behind this captivating design lies in"SOLAMENTR■"developed by Sumitomo Metal Mining Co.,Ltd.
文摘Outdoor jackets are engineered to protect against extreme weather while ensuring comfort and safety. Key to this protection is the thermal properties, achieved through insulation materials like down feathers and synthetic fibers, which trap heat and minimize heat loss. Resistance to wind, rain, and snow is provided by waterproof and windproof fabrics, while breathability allows moisture to escape, maintaining a comfortable microclimate. Air permeability and water resistance are essential for achieving this balance. This study examines two outdoor jacket prototypes with six material layers each. The outer layer (Layer 1) consists of 100% polyester coated with polyurethane for waterproofing. Inner layers (Layers 2, 3, and 6) use wool/cotton and wool/polyamide blends, offering insulation and moisture-wicking properties. Down feathers are used as the filling material, providing excellent warmth. Advanced materials like graphene and silver honeycomb fabrics were included to enhance thermal conductivity and regulate heat transfer. Performance testing focused on thermal conductivity, comfort (water and air permeability), and mechanical properties like tensile strength and tear resistance. Tests also assessed spray application and fastness to evaluate durability under environmental exposure. Results showed that jackets with silver-infused honeycomb fabrics had superior thermal conductivity, enabling better heat regulation and comfort in harsh conditions. The findings highlight the advantages of integrating silver honeycomb fabrics into outdoor jackets. These materials enhance insulation, thermal regulation, and overall comfort, making them ideal for high-performance designs. Incorporating such fabrics ensures functionality, durability, and user protection in extreme environments.
基金financially supported by the National Natural Science Foundation of China(Grant No.11472076).
文摘Jacket platforms constitute the foundational infrastructure of offshore oil and gas field exploitation.How to efficiently and accurately monitor the mechanical properties of jacket structures is one of the key problems to be solved to ensure the safe operation of the platform.To address the practical engineering problem that it is difficult to monitor the stress response of the tubular joints of jacket platforms online,a digital twin reduced-order method for real-time prediction of the stress response of tubular joints is proposed.In the offline construction phase,multi-scale modeling and multi-parameter experimental design methods are used to obtain the stress response data set of the jacket structure.Proper orthogonal decomposition is employed to extract the main feature information from the snapshot matrix,resulting in a reduced-order basis.The leave-one-out cross-validation method is used to select the optimal modal order for constructing the reduced-order model(ROM).In the online prediction phase,a digital twin model of the tubular joint is established,and the prediction performance of the ROM is analyzed and verified through using random environmental load and field environmental monitoring data.The results indicate that,compared with traditional numerical simulations of tubular joints,the ROM based on the proposed reduced-order method is more efficient in predicting the stress response of tubular joints while ensuring accuracy and robustness.
基金supports were received from the National Key Research and Development Program of China(2024YFE0208600)New Energy Joint Laboratory of China Southern Power Grid Corporation(GDXNY2024KF03)+2 种基金the National Natural Science Foundation of China(Grant No.U24B2090)National Key R&D Program(No.2022YFB4201300)Science and Technology Project of Huaneng Group(HNKJ24-H78).
文摘The jacket structure and transition piece comprise the supporting structure of a bottom-fixed offshore wind turbine(OWT)connected to the steel tower,which determines the overall structural dynamic performance of the entire OWT.Ideally,optimal performance can be realized by effectively coordinating two components,notwithstanding their separate design processes.In pursuit of this objective,this paper proposes a concurrent design methodology for the jacket structure and transition piece by exploiting topology optimization(TO).The TO for a three-legged jacket foundation is formulated by minimizing static compliance.In contrast to conventional TO,two separated volume fractions are imposed upon the structural design domain of the jacket structure and transition piece to ensure continuity.A 5 MW(megawatt)OWT supported by a four-legged or three-legged jacket substructure is under investigation.The external loads are derived from various design load cases that are acquired using the commercial software platform DNV Bladed(Det Norske Veritas).Through a comparative analysis of the fundamental frequency and maximum nodal deformation,it was found that the optimized solution demonstrates a reduced weight and superior stiffness.The findings demonstrate the present concurrent design approach using TO can yield significant benefits by reducing the overall design cycle and enhancing the feasibility of the final design.
文摘On the stage of China Media Group’s 2025 Spring Festival Gala,more than a dozen humanoid robots dressed in floral padded jackets danced alongside human counterparts in a creative folk dance performance.The robots not only smoothly twisted their waists and mimicked human leg-kicking movements,but also spun handkerchiefs,displaying extremely dexterous moves and exceptional skills.
基金funding from the National Natural Science Foundation of China(Grant Nos.12132003 and 12302460)。
文摘Compared with PELE with inert fillings such as polyethylene and nylon,reactive PELE(RPELE)shows excellent damage effects when impacting concrete targets due to the filling deflagration reaction.In present work,an analytical model describing the jacket deformation and concrete target damage impacted by RPELE was presented,in which the radial rarefaction and filling deflagration reaction were considered.The impact tests of RPELE on concrete target in the 592-1012 m/s were carried out to verify the analytical model.Based on the analytical model,the angle-length evolution mechanism of the jacket bending-curling deformation was revealed,and the concrete target damage was further analyzed.One can find out that the average prediction errors of the front crater,opening and back crater are 6.8%,8.5%and 7.1%,respectively.Moreover,the effects of radial rarefaction and deflagration were discussed.It was found that the neglect of radial rarefaction overestimates the jacket deformation and concrete target damage,while the deflagration reaction of filling increases the diameter of the front crater,opening and back crater by 25.4%,24.3%and 31.1%,respectively.The research provides a valuable reference for understanding and predicting the jacket deformation and concrete target damage impacted by RPELE.
文摘The tripod foundation(TF)is a prevalent foundation configuration in contemporary engineering practices.In comparison to a single pile,TF comprised interconnected individual piles,resulting in enhanced bearing capacity and stability.A physical model test was conducted within a sandy soil foundation,systematically varying the length-to-diameter ratio of the TF.The investigation aimed to comprehend the impact of altering the height of the central bucket on the historical horizontal bearing capacity of the foundation in saturated sand.Additionally,the study scrutinized the historical consequences of soil pressure and pore water pressure surrounding the bucket throughout the loading process.The historical findings revealed a significant enhancement in the horizontal bearing capacity of the TF under undrained conditions.When subjected to a historical horizontal loading angle of 0°for a single pile,the multi-bucket foundation exhibited superior historical bearing capacity compared to a single-pile foundation experiencing a historical loading angle of 180°under pulling conditions.With each historical increment in bucket height from 150 mm to 350 mm in 100 mm intervals,the historical horizontal bearing capacity of the TF exhibited an approximately 75%increase relative to the 150 mm bucket height,indicating a proportional relationship.Importantly,the historical internal pore water pressure within the bucket foundation remained unaffected by drainage conditions during loading.Conversely,undrained conditions led to a historical elevation in pore water pressure at the lower side of the pressure bucket.Consequently,in practical engineering applications,the optimization of the historical bearing efficacy of the TF necessitated the historical closure of the valve atop the foundation to sustain internal negative pressure within the bucket.This historical measure served to augment the historical horizontal bearing capacity.Simultaneously,historical external loads,such as wind,waves,and currents,were directed towards any individual bucket within the TF for optimal historical performance.
基金supported by the Tianjin Municipal Transportation Commission Project(No.2018-b2).
文摘The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position on the suppression effect.In this work,the wind-vortex-induced vibration of an elastic pipe of a deepwater jacket was studied,and vibrations were suppressed by using an NES.A van der Pol wake oscillator was used to simulate vortex-induced force,and the dynamic equation of the pipe considering the NES was established.The Galerkin method was applied to discretize the motion equation,and the vortex-induced vibration(VIV)of the pipe at reduced wind speeds was numerically analyzed.The novelty of this research is that particle swarm optimization was used to optimize the parameters of the NES to improve vibration suppression.The influence of the installation position,nonlinear stiffness,and damping parameters of the NES on vibration suppression was analyzed.Results showed that the optimized parameter combinations of the NES can effectively reduce wind-vortex-induced pipe vibration.The installation position of the NES had a significant effect on vibration suppression,and the midpoint of the pipe was the optimal NES installation position.An increase in stiffness or a 10% decrease in damping may cause vibration suppression failure.The results of this study provide some guidance for VIV suppression in deepwater jacket pipes.
基金co-funded by the Direction Générale de l'Armement (DGA)the French-German Institute of Saint Louis (ISL)。
文摘The evolution of threats and scenarios requires continuous performance improvements of ballistic protections for armed forces.From a modeling point of view,it is necessary to use sufficiently precise material behavior models to accurately describe the phenomena observed during the impact of a projectile on a protective equipment.In this context,the goal of this paper is to characterize the behavior of a small caliber steel jacket by combining experimental and numerical approaches.The experimental method is based on the lateral compression of ring specimens directly machined from the thin and small ammunition.Various speeds and temperatures are considered in a quasi-static regime in order to reveal the strain rate and temperature dependencies of the tested material.The Finite Element Updating Method(FEMU)is used.Experimental results are coupled with an inverse optimization method and a finite element numerical model in order to determine the parameters of a constitutive model representative of the jacket material.Predictions of the present model are verified against experimental results and a parametric study as well as a discussion on the identified material parameters are proposed.The results indicate that the strain hardening parameter can be neglected and the behavior of the thin steel jacket can be described by a modeling without strain hardening sensitivity.
文摘Columbia is a world-renowned manufacturer of outdoor products.Its product range covers all aspects of outdoor equipment such as jackets,down jackets,outdoor footwear,backpacks and accessories.In the outdoor industry,Columbia was the first brand to propose a three-in-one garment design concept.This practical design has since been adopted by almost every outdoor brand.The Columbia Jacket is positioned for urban outdoor recreation.Its rugged materials and design make it suitable for low-altitude outdoor sports as well as urban commuting.
文摘When the gentle breeze of spring starts to fill the air,it's often a time of transition,where the chill of winter gives way to the warmth of the coming season.However,for those who love the outdoors,spring can still present its own set of challenges,especially when it's time to choose the right jacket.Whether you're hiking in the hills,exploring the trails,or just taking a leisurely walk in the park,having a jacket that offers the perfect blend of warmth,comfort,and breathability is crucial.We'll delve into the various options available for jackets that are perfect for the outdoors in spring.
文摘Arc’teryx’s Beta AR Jacket sets a new bar in terms of what a mainstream outdoor jacket can do.You’ll turn around and charge headfirst into a rainstorm with this fully impermeable outer layer that packs in everything you need to lock in your core and stay dry.Unlike some jackets,the best part is that this jacket also pays dividends in sunny weather.While it’s designed for nasty weather,it stays comfortable when the storm passes away.The company’s high-tech waterproof membrane simultaneously wicks moisture and finally kicks that classic clammy raincoat feeling to the curb.
文摘In many cases, seismic appraisal of existing structures is carried out by the two step method and seismic strengthening of R.C. frame structures is solved just based on rough calculation or experience of designers, which may lead to either lack of safety or too conservative in design. According to some related criteria and experts experience, a computer program is developed specially for seismic appraisal and seismic strengthening of R.C. frames (not more than 10 storeys) in this paper. Because the progra...
