The testing on the bearing strength of single-shear bolt jointed composite laminates structure is done.And the effect of the fixture on the testing results is analyzed. Then a macro-micro multi-scale analytical model ...The testing on the bearing strength of single-shear bolt jointed composite laminates structure is done.And the effect of the fixture on the testing results is analyzed. Then a macro-micro multi-scale analytical model combined with the improved"Generalized Method of Cells( GMC) "is developed,which is used to predict the macro bearing strength and to characterize the micro constitute material failure of the bolt jointed composite laminates structure. Both the contact conditions at the bolt/hole boundary and the contact conditions at the specimen/fixture boundary,progressive damage,and the material properties degradation are all taken account into the analytical model. Thus,the numerical simulation results agree well with the experimental results.Finally,the effect of the fixture on the testing results is characterized. The results show that the incomplete contaction between the fixture and the specimen or the lack of the lateral constraint on the specimen will affect the limited bearing strength and the offset bearing strength of the bolt jointed composite laminates structure. In addition,the lower support rigid of the fixture will affect the rigid of the bolt jointed composite laminates structure.展开更多
Bioprinting is an emerging additive manufacturing technology that has enormous potential in bone implantation and repair. The insufficient accuracy of the shape of bioprinted parts is a primary clinical barrier that p...Bioprinting is an emerging additive manufacturing technology that has enormous potential in bone implantation and repair. The insufficient accuracy of the shape of bioprinted parts is a primary clinical barrier that prevents widespread utilization of bioprinting,especially for bone design with high-resolution requirements. During the last five years, the use of computer vision for process control has been widely practiced in the manufacturing field. Computer vision can improve the performance of bioprinting for bone research with respect to various aspects, including accuracy, resolution, and cell survival rate. Hence, computer vision plays a substantial role in addressing the current defect problem in bioprinting for bone research. In this review, recent advances in the application of computer vision in bioprinting for bone research are summarized and categorized into three groups based on different defect types: bone scaffold process control, deep learning, and cell viability models. The collection of printing parameters,data processing, and feedback of bioprinting information, which ultimately improves printing capabilities, are further discussed. We envision that computer vision may offer opportunities to accelerate bioprinting development and provide a new perception for bone research.展开更多
High-entropy alloys(HEA)represent a novel material class,with significant potential for research on performance and preparation in additive manufacturing(AM).Currently,FCC HEA dominates the research on AM-fabricated H...High-entropy alloys(HEA)represent a novel material class,with significant potential for research on performance and preparation in additive manufacturing(AM).Currently,FCC HEA dominates the research on AM-fabricated HEA,with a shift in focus from preparation to microstructure design and mechanical properties enhancement.Research on BCC HEA is currently primarily focused on preparation and process optimization.However,it is important to note that the biomedical potential of AM-fabricated BCC HEA should not be overlooked.This review provides a concise summary of the properties and preparation techniques of exceptional HEAs in recent years.It specifically emphasizes the novel microstructure achieved through AM techniques,which significantly enhance the mechanical properties of HEAs.Additionally,the review outlines the various preparation methods employed to mitigate defect introduction during AM processes.Finally,it offers insights into the future research directions and potential applications of additively manufactured HEA.展开更多
Air induction nozzles possess good anti-drift performance,the throat and orifice sizes of the nozzles are the main design parameters that affecting atomization.Therefore,Venturi tube nozzles and conventional flat fan ...Air induction nozzles possess good anti-drift performance,the throat and orifice sizes of the nozzles are the main design parameters that affecting atomization.Therefore,Venturi tube nozzles and conventional flat fan nozzles were assembled together to investigate the flow rate,droplet size,the quantity of air in droplets affected by a single design parameter of nozzles with applying high speed camera and Spraytec laser diffraction system.The results showed that:the flow rate of the air induction nozzle depended only on the throat size of Venturi tube and pressure,and it was proportional to the throat size of Venturi tube at the same pressure;The flat fan nozzle’s orifice size and Venturi tube size significantly affected volume median diameter of droplets,which generally increased after adding surfactant;A new model was established after optimizing classical equation for calculating the percentage of intake air in droplets and studying the effects of throat and orifice size of air induction nozzles on spray characteristics.By variance analysis,it was verified that the new model of quantity of air in droplets produced by all connected nozzles was correct.The calculation showed that the bubbles sizes ranged at 200-900μm and were in proportion to the droplet size with the percentage of intake air of 10%to 90%.Contrast to the change of volume median diameter and droplet velocity,the existence of intake air could influence their change degree to some extent.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.11272105)the Heilongjiang Province Science Foundation for Youths(Grant No.QC2015003)the Harbin Science and Technology Bureau Young Talent Reserve Project(Grant No.RC2016QN001011,RC2016QN017023)
文摘The testing on the bearing strength of single-shear bolt jointed composite laminates structure is done.And the effect of the fixture on the testing results is analyzed. Then a macro-micro multi-scale analytical model combined with the improved"Generalized Method of Cells( GMC) "is developed,which is used to predict the macro bearing strength and to characterize the micro constitute material failure of the bolt jointed composite laminates structure. Both the contact conditions at the bolt/hole boundary and the contact conditions at the specimen/fixture boundary,progressive damage,and the material properties degradation are all taken account into the analytical model. Thus,the numerical simulation results agree well with the experimental results.Finally,the effect of the fixture on the testing results is characterized. The results show that the incomplete contaction between the fixture and the specimen or the lack of the lateral constraint on the specimen will affect the limited bearing strength and the offset bearing strength of the bolt jointed composite laminates structure. In addition,the lower support rigid of the fixture will affect the rigid of the bolt jointed composite laminates structure.
基金National Natural Science Foundation of China under (Grant Nos. 52011530181 and 51831011)Shanghai Science and Technology Commission under Grant No. 20S31900100+1 种基金Guangxi Science and Technology Program:The central government guides the local sciencetechnology development science and technology innovation base project (Guike Jizi[2020]No. 198):Basic Research and Transformation Technology Innovation Base of Bone and Joint Degenerative Diseases
文摘Bioprinting is an emerging additive manufacturing technology that has enormous potential in bone implantation and repair. The insufficient accuracy of the shape of bioprinted parts is a primary clinical barrier that prevents widespread utilization of bioprinting,especially for bone design with high-resolution requirements. During the last five years, the use of computer vision for process control has been widely practiced in the manufacturing field. Computer vision can improve the performance of bioprinting for bone research with respect to various aspects, including accuracy, resolution, and cell survival rate. Hence, computer vision plays a substantial role in addressing the current defect problem in bioprinting for bone research. In this review, recent advances in the application of computer vision in bioprinting for bone research are summarized and categorized into three groups based on different defect types: bone scaffold process control, deep learning, and cell viability models. The collection of printing parameters,data processing, and feedback of bioprinting information, which ultimately improves printing capabilities, are further discussed. We envision that computer vision may offer opportunities to accelerate bioprinting development and provide a new perception for bone research.
基金The authors acknowledge the financial supports from National Natural Science Foundation of China(Grant Nos.51831011,52011530181)the Shanghai Science and Technology Commission(Grant No.20S31900100).
文摘High-entropy alloys(HEA)represent a novel material class,with significant potential for research on performance and preparation in additive manufacturing(AM).Currently,FCC HEA dominates the research on AM-fabricated HEA,with a shift in focus from preparation to microstructure design and mechanical properties enhancement.Research on BCC HEA is currently primarily focused on preparation and process optimization.However,it is important to note that the biomedical potential of AM-fabricated BCC HEA should not be overlooked.This review provides a concise summary of the properties and preparation techniques of exceptional HEAs in recent years.It specifically emphasizes the novel microstructure achieved through AM techniques,which significantly enhance the mechanical properties of HEAs.Additionally,the review outlines the various preparation methods employed to mitigate defect introduction during AM processes.Finally,it offers insights into the future research directions and potential applications of additively manufactured HEA.
基金supported by National Key Research and Development Program(No.2016YFD0200706)Heilongjiang Bayi Agricultural University Academic Achievement Introduction Project(No.XDB2013-08)+1 种基金Natural Science Outstanding Youth Project of Heilongjiang Province of China(No.YQ2019E032)University Level Key Project of Heilongjiang Bayi Agricultural University(No.XA2015-01).
文摘Air induction nozzles possess good anti-drift performance,the throat and orifice sizes of the nozzles are the main design parameters that affecting atomization.Therefore,Venturi tube nozzles and conventional flat fan nozzles were assembled together to investigate the flow rate,droplet size,the quantity of air in droplets affected by a single design parameter of nozzles with applying high speed camera and Spraytec laser diffraction system.The results showed that:the flow rate of the air induction nozzle depended only on the throat size of Venturi tube and pressure,and it was proportional to the throat size of Venturi tube at the same pressure;The flat fan nozzle’s orifice size and Venturi tube size significantly affected volume median diameter of droplets,which generally increased after adding surfactant;A new model was established after optimizing classical equation for calculating the percentage of intake air in droplets and studying the effects of throat and orifice size of air induction nozzles on spray characteristics.By variance analysis,it was verified that the new model of quantity of air in droplets produced by all connected nozzles was correct.The calculation showed that the bubbles sizes ranged at 200-900μm and were in proportion to the droplet size with the percentage of intake air of 10%to 90%.Contrast to the change of volume median diameter and droplet velocity,the existence of intake air could influence their change degree to some extent.