摘要
建立细长缆索大柔性多体动力学模型时,现实存在的复杂捻制几何构型多不予考虑,而是将柔索简化为材料均匀梁进行描述,致使运动仿真模型与物理实际存在一定差距.为此,研究一种典型非线性拧绞绳股的大变形等效动力学建模方法,考虑准静态与大范围运动情况下绳股内的线接触,计算了受摩擦力及弯曲曲率影响的绳股可变弯曲刚度,通过等效梁模型避免了绳股精细建模时的大规模计算消耗.基于连续介质力学与绝对节点坐标方法,建立了拧绞绳惯性广义坐标下的多柔体动力学模型.为了验证等效模型的可行性,与基于有限段方法建立的精细模型进行对比仿真分析,通过位形验证了等效模型的精度.进一步地,根据力载作用下的准静态构型,研究了特定构型绳股弯曲刚度沿轴向的分布规律;通过自重力下一端固定柔性绳摆自由运动仿真并与传统均匀梁模型相比,研究了模型弯曲特性的差异.最后,根据能量守恒原理分析了摩擦耗散系统内各种能量间的相互转化.拧绞绳大变形等效动力学模型能够提高绳索动力系统运动预测的仿真计算效率,还能为钢丝绳参数与构型设计提供依据.
When modeling the slender structures such as cable and tether with large flexibility,the complex twirling geometry in practical situation is usually ignored and the cable is simplified as a general beam with homogeneous material.In doing so,the result of dynamic simulation diverges from the physical significance.Therefore,this paper provides an equivalent dynamic method for the typical nonlinear helix wire strand considering the inner line contact under the static and large scale dynamic conditions.The variable bending stiffness affected by the contact friction and bending curvature is obtained through the equivalent constitutive law,by which the massive computation resulting from fine modeling method is able to be avoided.Based on the absolute nodal coordinate formulation,a series of the generalized coordinates have been selected to establish the dynamic differential equations.To verify the equivalent method,a fine strand model based on the finite segment element has been provided to test the accuracy according to the practical strand configuration.Furtherer,the distribution of the variable bending stiffness in practical strand under certain load is obtained through the quasi-static analysis.Compared with traditional ANCF model,the dynamic simulation of the one-tip-fixed equivalent beam under gravity coincides with the fact that the stiffness decreases as well as the flexibility increases in twirling strand.At last,the conversion among each kind of the energy component has been researched.The equivalent model of the twirling strand with large deformation can be used to improve the efficiency of the motion prediction in cable dynamic systems.Besides,the results provide the evidence for wire rope design.
作者
过佳雯
魏承
谭春林
赵阳
Guo Jiawen;Wei Cheng;Tan Chunlin;Zhao Yang(School of Astronautics,Harbin Institute of Technology,Harbin 150001,China;China Academy of Space Technology,Beijing 100086,China)
出处
《力学学报》
EI
CSCD
北大核心
2018年第2期373-384,共12页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家重点基础研究发展计划(973计划)(2013CB733004)和微小型航天器技术国防重点学科实验室开放基金(HIT.KLOF.MST.201703)资助项目.
关键词
拧绞绳
可变弯曲刚度
大变形
绝对节点坐标法
接触摩擦
stranded wire rope
variable bending stiffness
large deformation
absolute nodal coordinate formulation,contact friction
