Marine pipeline damage subjected to dropped objects from platforms or supply vessels is analyzed to introduce an easy and applicable approach to investigating the damage induced by impact load from drop weight. A prac...Marine pipeline damage subjected to dropped objects from platforms or supply vessels is analyzed to introduce an easy and applicable approach to investigating the damage induced by impact load from drop weight. A practical engineering example was presented and analyzed using the commercial program 'ANSYS/LS-DYNA', which is a powerful tool with an explicit dynamic solver. And rational agreement of the results with previous works was obtained. The suggested procedure might be taken as a checking analysis of the protection measures of pipelines in addition to the general risk assessment method.展开更多
Plain concrete plate and fiber concrete plate subjected to temperature drop load were analyzed on stochastic finite element method (FEM).It is found that fibers can enhance concrete ability to resist tem- perature dro...Plain concrete plate and fiber concrete plate subjected to temperature drop load were analyzed on stochastic finite element method (FEM).It is found that fibers can enhance concrete ability to resist tem- perature drop load for improving concrete's fracture energy and deferring the crack process.It is found for concrete not to improve apparently its tensile strength and fracture energy is recommended to be its appraisal parameter.展开更多
H-steel all-bolted connection steel frame structures with heat preservation and decoration composite wall boards were investigated and the seismic performances of three scaled specimens were studied.The failure modes,...H-steel all-bolted connection steel frame structures with heat preservation and decoration composite wall boards were investigated and the seismic performances of three scaled specimens were studied.The failure modes,hysteresis curves,bearing capacity,ductility,energy dissipation capacity,stiffness degradation and strain distribution were discussed.The calculation method of structural theoretical internal force was presented.The results showed that the overall structural seismic performance was better,and the structural ductility met the demands of elastic-plastic inter-story drift angle for seismic design.The H-steel weak-axis connection structure obtained better energy dissipation capacity,and its bearing capacity and stiffness were slightly different from the strong-axis connection.The heat preservation and decoration performance of composite wallboard and the all-bolted connection of the steel frame realized prefabrication during the whole construction period.The plastic hinge of the steel beam can be moved outwards because of the L-angles,which effectively avoids stress concentration in joint areas and expands the plastic hinge range.The errors between the theoretical structural capacity calculated by the plastic analysis method and the test results were within 2.44%.In addition,structural failure mechanisms and bearing capacities were verified by the finite element(FE)analysis,and the effects of the main parameters on the structures were investigated.The FE verification results were the same as in the test.The research results provide theoretical support and technical guidance for the application of thermal insulation and decorative composite wall panels in H-shaped steel all-bolted steel frames.展开更多
This study focuses on the effect of lateral mass impact on ring-stiffened thin-walled cylindrical shell.Cylindrical shells were fabricated to validate the numerical modeling and analytical techniques,and drop tests we...This study focuses on the effect of lateral mass impact on ring-stiffened thin-walled cylindrical shell.Cylindrical shells were fabricated to validate the numerical modeling and analytical techniques,and drop tests were performed using a rigid spherical indenter.Next,stiffened-ring cylindrical shells with various structural size parameters were simulated using ABAQUS software.The relationships between the impact force,deformation displacement,and rebound velocity were established,on the basis of impact mechanics theory and simulation results.It derived fitting functions to analyse the relationship between the maximum load and maximum displacement of ring-stiffened cylindrical shell under dynamic mass impact.Based on the validation of the simulation model,the fitting function data were compared with the simulation results,and the functions showed a good accuracy.Besides,the parameters,mass ratio and stiffened-ring mass ratio were used to reflect the effect of the mass change in the ring-stiffened cylindrical shell.Furthermore,parametric studies on ring-stiffened cylindrical shell models were conducted to analyse the progressive impact responses.展开更多
This study explains the relationship between friction coefficient and pressure change at a range of Reynolds (21,056 - 28,574) and (0 - 1.4) solid loading ratio of two-phase flow (gas-solid) inside a circular copper p...This study explains the relationship between friction coefficient and pressure change at a range of Reynolds (21,056 - 28,574) and (0 - 1.4) solid loading ratio of two-phase flow (gas-solid) inside a circular copper pipe by using laboratory apparatus and solving the equations mathematically. An experimentally relationship of friction coefficient and pressure change with Reynolds number and flow velocity obtained also the relationship between the Solid loading ratio with friction coefficient and pressure change has been done for a Limit range of Reynolds number. It was noticed that the increase in friction coefficient and pressure change for two-phase flow was occurred when solid loading ratio increased. Also the relationship between pressure change and Reynolds number was direct proportion while the relationship between friction coefficient and Reynolds Number was inversely related.展开更多
We studied consecutive impact loading on woven high-modulus polyethylene rope, which is used in robotics fields. An impact tester was developed to conduct the experiments. Five consecutive impact loads (five drops) we...We studied consecutive impact loading on woven high-modulus polyethylene rope, which is used in robotics fields. An impact tester was developed to conduct the experiments. Five consecutive impact loads (five drops) were applied to the rope and the stiffness of the loading part that corresponds to each drop was evaluated. The stiffness of the woven ropes was affected strongly by consecutive impact loading. The change in stiffness is undesirable in some applications such as in robotic fields. Therefore, we have proposed a method that can optimize changes in stiffness by applying a preload before impact testing (preload treatment). The experimental results show that preload is an efficient way to reduce changing rope stiffness. We have also proposed an empirical equation that can estimate the rope stiffness after arbitrary preload treatment, and this equation is a function of the number of drops and the static preload level. The equation can be used to determine the preload treatment conditions to stabilize the stiffness of the woven ropes before they are used in engineering fields.展开更多
An experimental study was carried out to investigate the amount of drugs loaded on microneedles. The microneedles were made with poly (lactic acid). Aqueous poly (vinyl alcohol) solutions were prepared as drug solutio...An experimental study was carried out to investigate the amount of drugs loaded on microneedles. The microneedles were made with poly (lactic acid). Aqueous poly (vinyl alcohol) solutions were prepared as drug solutions. Two drug loading approaches, i.e., dropping and dipping, were examined. It was found that capillary number is the only relevant dimensionless group for the two methods. For the dropping approach, dried drugs will spread near the bottom of a microneedle patch provided the surface tension is low. As for the dipping approach, both a single microneedle and an array of nine microneedles were examined. For a single microneedle, high capillary rises before pulling and pulling speed are two key factors to increase the drug loading volume. For an array of microneedles, the effect of capillary rise owing to the interaction between microneedles would increase the drug loading volume several times higher than a single microneedle of the same dimension.展开更多
文摘Marine pipeline damage subjected to dropped objects from platforms or supply vessels is analyzed to introduce an easy and applicable approach to investigating the damage induced by impact load from drop weight. A practical engineering example was presented and analyzed using the commercial program 'ANSYS/LS-DYNA', which is a powerful tool with an explicit dynamic solver. And rational agreement of the results with previous works was obtained. The suggested procedure might be taken as a checking analysis of the protection measures of pipelines in addition to the general risk assessment method.
文摘Plain concrete plate and fiber concrete plate subjected to temperature drop load were analyzed on stochastic finite element method (FEM).It is found that fibers can enhance concrete ability to resist tem- perature drop load for improving concrete's fracture energy and deferring the crack process.It is found for concrete not to improve apparently its tensile strength and fracture energy is recommended to be its appraisal parameter.
文摘H-steel all-bolted connection steel frame structures with heat preservation and decoration composite wall boards were investigated and the seismic performances of three scaled specimens were studied.The failure modes,hysteresis curves,bearing capacity,ductility,energy dissipation capacity,stiffness degradation and strain distribution were discussed.The calculation method of structural theoretical internal force was presented.The results showed that the overall structural seismic performance was better,and the structural ductility met the demands of elastic-plastic inter-story drift angle for seismic design.The H-steel weak-axis connection structure obtained better energy dissipation capacity,and its bearing capacity and stiffness were slightly different from the strong-axis connection.The heat preservation and decoration performance of composite wallboard and the all-bolted connection of the steel frame realized prefabrication during the whole construction period.The plastic hinge of the steel beam can be moved outwards because of the L-angles,which effectively avoids stress concentration in joint areas and expands the plastic hinge range.The errors between the theoretical structural capacity calculated by the plastic analysis method and the test results were within 2.44%.In addition,structural failure mechanisms and bearing capacities were verified by the finite element(FE)analysis,and the effects of the main parameters on the structures were investigated.The FE verification results were the same as in the test.The research results provide theoretical support and technical guidance for the application of thermal insulation and decorative composite wall panels in H-shaped steel all-bolted steel frames.
基金supported by the National Natural Science Foundation of China(Grant No.51508123,named“Study on blast response of floating roof storage tank in material point method”)Natural Science Foundation of Heilongjiang Province,China(LH2019A008)to provide fund for conducting experiments and research.The authors would like to acknowledge Professor Wei Wang in Harbin Institute of Technology for instructions and help in experiment design.
文摘This study focuses on the effect of lateral mass impact on ring-stiffened thin-walled cylindrical shell.Cylindrical shells were fabricated to validate the numerical modeling and analytical techniques,and drop tests were performed using a rigid spherical indenter.Next,stiffened-ring cylindrical shells with various structural size parameters were simulated using ABAQUS software.The relationships between the impact force,deformation displacement,and rebound velocity were established,on the basis of impact mechanics theory and simulation results.It derived fitting functions to analyse the relationship between the maximum load and maximum displacement of ring-stiffened cylindrical shell under dynamic mass impact.Based on the validation of the simulation model,the fitting function data were compared with the simulation results,and the functions showed a good accuracy.Besides,the parameters,mass ratio and stiffened-ring mass ratio were used to reflect the effect of the mass change in the ring-stiffened cylindrical shell.Furthermore,parametric studies on ring-stiffened cylindrical shell models were conducted to analyse the progressive impact responses.
文摘This study explains the relationship between friction coefficient and pressure change at a range of Reynolds (21,056 - 28,574) and (0 - 1.4) solid loading ratio of two-phase flow (gas-solid) inside a circular copper pipe by using laboratory apparatus and solving the equations mathematically. An experimentally relationship of friction coefficient and pressure change with Reynolds number and flow velocity obtained also the relationship between the Solid loading ratio with friction coefficient and pressure change has been done for a Limit range of Reynolds number. It was noticed that the increase in friction coefficient and pressure change for two-phase flow was occurred when solid loading ratio increased. Also the relationship between pressure change and Reynolds number was direct proportion while the relationship between friction coefficient and Reynolds Number was inversely related.
文摘We studied consecutive impact loading on woven high-modulus polyethylene rope, which is used in robotics fields. An impact tester was developed to conduct the experiments. Five consecutive impact loads (five drops) were applied to the rope and the stiffness of the loading part that corresponds to each drop was evaluated. The stiffness of the woven ropes was affected strongly by consecutive impact loading. The change in stiffness is undesirable in some applications such as in robotic fields. Therefore, we have proposed a method that can optimize changes in stiffness by applying a preload before impact testing (preload treatment). The experimental results show that preload is an efficient way to reduce changing rope stiffness. We have also proposed an empirical equation that can estimate the rope stiffness after arbitrary preload treatment, and this equation is a function of the number of drops and the static preload level. The equation can be used to determine the preload treatment conditions to stabilize the stiffness of the woven ropes before they are used in engineering fields.
文摘An experimental study was carried out to investigate the amount of drugs loaded on microneedles. The microneedles were made with poly (lactic acid). Aqueous poly (vinyl alcohol) solutions were prepared as drug solutions. Two drug loading approaches, i.e., dropping and dipping, were examined. It was found that capillary number is the only relevant dimensionless group for the two methods. For the dropping approach, dried drugs will spread near the bottom of a microneedle patch provided the surface tension is low. As for the dipping approach, both a single microneedle and an array of nine microneedles were examined. For a single microneedle, high capillary rises before pulling and pulling speed are two key factors to increase the drug loading volume. For an array of microneedles, the effect of capillary rise owing to the interaction between microneedles would increase the drug loading volume several times higher than a single microneedle of the same dimension.
