点阵材料具有轻质、抗冲击、高能量吸收等特性,因而在航天飞行器承载部件设计等领域有广阔应用前景.通过对点阵材料内部杆径进行合理的梯度设计,可以提高点阵材料在高速冲击载荷作用下的动态力学性能.利用仿真模拟数据,基于随机森林模...点阵材料具有轻质、抗冲击、高能量吸收等特性,因而在航天飞行器承载部件设计等领域有广阔应用前景.通过对点阵材料内部杆径进行合理的梯度设计,可以提高点阵材料在高速冲击载荷作用下的动态力学性能.利用仿真模拟数据,基于随机森林模型实现了梯度点阵材料的动态力学响应预测和结构参数优化.以面心立方(face center cubic,FCC)结构梯度点阵材料为研究对象,通过对杆径参数的调整实现点阵材料密度的梯度化设计.通过LS-DYNA软件计算了密度分布不同的梯度点阵材料受到冲击载荷作用时的动态力学响应,包括冲击端面与支撑端面接触应力随时间的变化曲线.基于随机森林模型,以各层胞元的相对密度为输入,实现对点阵材料端面峰值应力的预测,并基于Gini指数分析出对不同端面处峰值应力影响最大的胞元层.将网格搜索算法与训练好的随机森林对接,分别以两个端面上的峰值应力最高作为优化目标,获得点阵材料各层胞元相对密度的最优值.模型对梯度点阵材料端面峰值应力的预测误差在5%以内.数值模拟验证结果表明,优化后所得梯度点阵材料相应端面上的峰值应力高于仿真数据集内任何结构.展开更多
In a vast number of engineering fields like medicine,aerospace or robotics,materials are required to meet unusual performances that simple homogeneous materials are often not able to fulfil.Consequently,many efforts a...In a vast number of engineering fields like medicine,aerospace or robotics,materials are required to meet unusual performances that simple homogeneous materials are often not able to fulfil.Consequently,many efforts are currently devoted to develop future generations of materials with enhanced properties and unusual functionalities.In many instances,biological systems served as a source of inspiration,as in the case of cellular materials.Commonly observed in nature,cellular materials offer useful combinations of structural properties and low weight,yielding the possibility of coexistence of what used to be antagonistic physical properties within a single material.Due to their peculiar characteristics,they are very promising for engineering applications in a variety of industries including aerospace,automotive,marine and constructions.However,their use is conditional upon the development of appropriate constitutive models for revealing the complex relations between the microstructure's parameters and the macroscopic behavior.From this point of view,a great variety of analytical and numerical techniques have been proposed and exhaustively discussed in recent years.Noteworthy contributions,suggesting different assumptions and techniques are critically presented in this review paper.展开更多
文摘点阵材料具有轻质、抗冲击、高能量吸收等特性,因而在航天飞行器承载部件设计等领域有广阔应用前景.通过对点阵材料内部杆径进行合理的梯度设计,可以提高点阵材料在高速冲击载荷作用下的动态力学性能.利用仿真模拟数据,基于随机森林模型实现了梯度点阵材料的动态力学响应预测和结构参数优化.以面心立方(face center cubic,FCC)结构梯度点阵材料为研究对象,通过对杆径参数的调整实现点阵材料密度的梯度化设计.通过LS-DYNA软件计算了密度分布不同的梯度点阵材料受到冲击载荷作用时的动态力学响应,包括冲击端面与支撑端面接触应力随时间的变化曲线.基于随机森林模型,以各层胞元的相对密度为输入,实现对点阵材料端面峰值应力的预测,并基于Gini指数分析出对不同端面处峰值应力影响最大的胞元层.将网格搜索算法与训练好的随机森林对接,分别以两个端面上的峰值应力最高作为优化目标,获得点阵材料各层胞元相对密度的最优值.模型对梯度点阵材料端面峰值应力的预测误差在5%以内.数值模拟验证结果表明,优化后所得梯度点阵材料相应端面上的峰值应力高于仿真数据集内任何结构.
文摘In a vast number of engineering fields like medicine,aerospace or robotics,materials are required to meet unusual performances that simple homogeneous materials are often not able to fulfil.Consequently,many efforts are currently devoted to develop future generations of materials with enhanced properties and unusual functionalities.In many instances,biological systems served as a source of inspiration,as in the case of cellular materials.Commonly observed in nature,cellular materials offer useful combinations of structural properties and low weight,yielding the possibility of coexistence of what used to be antagonistic physical properties within a single material.Due to their peculiar characteristics,they are very promising for engineering applications in a variety of industries including aerospace,automotive,marine and constructions.However,their use is conditional upon the development of appropriate constitutive models for revealing the complex relations between the microstructure's parameters and the macroscopic behavior.From this point of view,a great variety of analytical and numerical techniques have been proposed and exhaustively discussed in recent years.Noteworthy contributions,suggesting different assumptions and techniques are critically presented in this review paper.
