近场动力学(peridynamics, PD)模拟复合材料分层损伤,相较于传统的数值方法有一定优势。双悬臂梁试验(double cantilever beam, DCB)是测量复合材料I型层间断裂韧性 G IC 的标准试验。本文研究了复合材料双悬臂梁试验I型分层扩展过程的...近场动力学(peridynamics, PD)模拟复合材料分层损伤,相较于传统的数值方法有一定优势。双悬臂梁试验(double cantilever beam, DCB)是测量复合材料I型层间断裂韧性 G IC 的标准试验。本文研究了复合材料双悬臂梁试验I型分层扩展过程的三维近场动力学模拟。计算模型选用了球型域的常规态近场动力学复合材料模型,并引入了基于能量的失效判定准则。结果表明,近场动力学模拟的载荷-位移曲线与试验结果吻合得很好,并且模拟结果能够捕捉到DCB试验的“指甲盖形”分层前缘。在此基础上,进一步比较了I型分层扩展过程的近场动力学模拟结果与试验结果,验证了本文采用的复合材料近场动力学模型计算I型分层扩展的有效性。展开更多
In the past few decades,the navigation performance of ships and structures in ice-covered waters has not been fully studied,especially the influence of ice mechanical properties on icebreaking ability.Ice bending stre...In the past few decades,the navigation performance of ships and structures in ice-covered waters has not been fully studied,especially the influence of ice mechanical properties on icebreaking ability.Ice bending strength is a key ice parameter for predicting ship ice loads,and accurate ice bending strength is also the key to scaling model tests results to real ship.However,numerical simulation studies on model ice bending strength of ice tanks are often neglected.In this paper,an explicit finite element method model is used to simulate the ice cantilever beam test,and the failure load and bending strength of the ice are obtained.In this model,the Tsai-Wu failure criterion is used as the material constitutive model,and the required simulation parameters are obtained from the model ice test in ice tank.Parameter sensitivity analysis shows that the cantilever beam size of the model ice has a significant effect on the flexural strength.The results show that proper rounding at the root of the cantilever beam is beneficial to reduce stress concentration and obtain more accurate bending strength;the thickness,width and length of the cantilever beam should conform to a certain ratio,and consistent with the ITTC recommended reference.Therefore,the results of this study can promote model ice experiments and numerical studies and provide ice strength data support for ship design and polar ship maneuvering.展开更多
针对夹芯复合材料T型连接结构,建立了有限元模型,模拟其在悬臂弯曲位移载荷下损伤产生、扩展及失效的过程,进行了悬臂弯曲试验验证模拟结果,进行了结构优化分析。试验结果表明:初始损伤产生时的位移为30 mm^32 mm,对应载荷为7.5 k N^7.7...针对夹芯复合材料T型连接结构,建立了有限元模型,模拟其在悬臂弯曲位移载荷下损伤产生、扩展及失效的过程,进行了悬臂弯曲试验验证模拟结果,进行了结构优化分析。试验结果表明:初始损伤产生时的位移为30 mm^32 mm,对应载荷为7.5 k N^7.7 k N,损伤产生后结构刚度降低,随着位移增加,承载力持续上升,失效强度较初始损伤强度提高了41%~55%;计算结果与试验结果相吻合,且表明初始损伤为复合材料压缩失效,产生于隔板下面板与增强区连接处,随着位移载荷的增加,损伤面积增大最终导致整体结构失效;优化结果表明,提高隔板下面板和芯材厚度,可降低隔板下面板的最大应力和失效因子,缩小上下面板的失效因子差,充分发挥结构性能。展开更多
文摘近场动力学(peridynamics, PD)模拟复合材料分层损伤,相较于传统的数值方法有一定优势。双悬臂梁试验(double cantilever beam, DCB)是测量复合材料I型层间断裂韧性 G IC 的标准试验。本文研究了复合材料双悬臂梁试验I型分层扩展过程的三维近场动力学模拟。计算模型选用了球型域的常规态近场动力学复合材料模型,并引入了基于能量的失效判定准则。结果表明,近场动力学模拟的载荷-位移曲线与试验结果吻合得很好,并且模拟结果能够捕捉到DCB试验的“指甲盖形”分层前缘。在此基础上,进一步比较了I型分层扩展过程的近场动力学模拟结果与试验结果,验证了本文采用的复合材料近场动力学模型计算I型分层扩展的有效性。
文摘In the past few decades,the navigation performance of ships and structures in ice-covered waters has not been fully studied,especially the influence of ice mechanical properties on icebreaking ability.Ice bending strength is a key ice parameter for predicting ship ice loads,and accurate ice bending strength is also the key to scaling model tests results to real ship.However,numerical simulation studies on model ice bending strength of ice tanks are often neglected.In this paper,an explicit finite element method model is used to simulate the ice cantilever beam test,and the failure load and bending strength of the ice are obtained.In this model,the Tsai-Wu failure criterion is used as the material constitutive model,and the required simulation parameters are obtained from the model ice test in ice tank.Parameter sensitivity analysis shows that the cantilever beam size of the model ice has a significant effect on the flexural strength.The results show that proper rounding at the root of the cantilever beam is beneficial to reduce stress concentration and obtain more accurate bending strength;the thickness,width and length of the cantilever beam should conform to a certain ratio,and consistent with the ITTC recommended reference.Therefore,the results of this study can promote model ice experiments and numerical studies and provide ice strength data support for ship design and polar ship maneuvering.
文摘针对夹芯复合材料T型连接结构,建立了有限元模型,模拟其在悬臂弯曲位移载荷下损伤产生、扩展及失效的过程,进行了悬臂弯曲试验验证模拟结果,进行了结构优化分析。试验结果表明:初始损伤产生时的位移为30 mm^32 mm,对应载荷为7.5 k N^7.7 k N,损伤产生后结构刚度降低,随着位移增加,承载力持续上升,失效强度较初始损伤强度提高了41%~55%;计算结果与试验结果相吻合,且表明初始损伤为复合材料压缩失效,产生于隔板下面板与增强区连接处,随着位移载荷的增加,损伤面积增大最终导致整体结构失效;优化结果表明,提高隔板下面板和芯材厚度,可降低隔板下面板的最大应力和失效因子,缩小上下面板的失效因子差,充分发挥结构性能。
