移动线载荷板局部非线性响应的网格重划分数值方法

Rezoning method in nonlinear simulation of plate under moving load

  • 摘要: 在船舶建造中,常涉及板的焊接、线加热、局部滚压成型等加工方式。该加工方式中的载荷作用区域相对于板的尺度较窄且具有高度的非线性特征,同时载荷稳定移动。把握加工参数与响应的关系在加工过程中很重要。由于载荷移动导致板局部非线性响应的特性不断随之变化,故其相应的计算非常复杂。常规的数值方法是主要采用的手段,但由于该方法在载荷全局作用区域上需预先将网格细密划分,导致计算效率低下。如果考虑到在该加工方式中载荷作用区域之外的大部分区域处于弱非线性或线弹性状态,在数值模拟中将载荷当前作用区域的单元划分细密,远离载荷作用区域划分得相对较粗疏,同时载荷移动时细密网格随着载荷一起移动,即采用网格重划分数值方法来分析上述问题就能节省大量计算时间。针对该方法,重点探究细密网格尺寸以及网格重划分频度对数值计算的影响及其与计算效率和精度的关系,并以板局部滚压成型加工为例进行数值计算。结果表明,该方法可作为移动载荷作用下板局部非线性响应的一种高效的计算手段。

     

    Abstract: Ship building includes line heating, welding, local roll forming and other processing methods for plates. Compared to the plate dimensions, the region under steady moving linear load in the processing method is narrow with highly nonlinear characteristics. How to coordinate the relationship between the process parameters and the response is one of the main contents of the process. Since the linear load moves on the plate, the characteristics of local nonlinear response keep changing continuously, demanding complicated calculations. Because the mesh for the global region under linear load should be fine, conventional numerical methods result in low efficiency. When considering that other regions away from the loading area in the processing remain weak, nonlinear or elastic, the mesh for the region under current loads can be fine, while the mesh for another region away from the load may be relatively coarser in numerical simulations, with fine mesh moving along with the moving loads, i.e. the rezoning numerical method, which can save much computational time. In this paper, the impact of fine mesh size and rezoning frequency on the numerical computation, and the relationship with numerical accuracy and computational efficiency were researched using this method. The numerical computation example of the local rolling forming process was carried out, resulting in the impact of fine mesh size and rezoning frequency on the computational efficiency and numerical accuracy of the rezoning numerical method. The efficient numerical computation means of plates under moving linear loads with local nonlinear response verify the effectiveness of the method.

     

/

返回文章
返回