基于ANCF的松弛绳索动力学建模与仿真

传统绝对节点坐标方法(ANCF)绳索模型是基于梁单元建立的,其不能反映纤维绳索的不可抗压和松弛特性。考虑纤维绳索初始松弛余量,给出了绳索非线性轴向应力-应变关系。绳索在松弛状态下轴向力接近于零,在张紧状态下表现出线弹性特性。在此基础上,采用绝对节点坐标方法推导了松弛绳索动力学模型。通过静力学和动力学仿真,将传统绳索模型和松弛绳索模型进行对比,结果表明:在重力及不同集中载荷作用下,松弛绳索相比于传统绳索都具有更大的变形;分析移除集中载荷后绳索的动力学响应可知,传统绳索在振动过程中始终处于张紧状态,且绳索上各点振动同步,而松弛绳索会在张紧和松弛状态之间不断转换,绳索上各点的振动存在相位差,能够更好地反映绳索在松弛状态下的动力学特性。

Dynamic modeling and simulation of slack rope based on ANCF

Traditional absolute nodal coordinate formulation (ANCF) rope model is built based on beam element,and cannot reflect the incompressible and slack properties of fiber ropes.Considering the initial slackness of fiber ropes,the nonlinear axial stress-strain relationship of the rope is presented.The axial force of the rope is close to zero in the slack state,while the rope shows linear elastic property in the tense state.On this basis,the dynamic model of the slack rope is derived by applying ANCF.The traditional rope model and slack rope model are compared with each other through static and dynamic simulations,and the results indicate that compared with the traditional rope,the slack rope has greater deformation under gravity and different concentrated loads.According to the dynamic response of the rope after removal of the concentrated load,it is found that the traditional rope is always in tense state in the vibration process and the vibration of each point is synchronous;however,the slack rope keeps shifting in tense and slack states and there exists phase difference between each point,which can better reflect the dynamic characteristics of the rope in the slack state.