Abstract: The boundary element method (BEM) in injection molding cooling analysis generate full-matrix equations. If the element number is too large, its calculating work will be beyond the computer’s ability. There is no valid numerical method to solve these equations today. The key problem is the computation speed.This not only means a long time of computation, but also means that the calculation does not convergent easily.This paper presents a new method to deal with the problem. Because the temperature variation on mold surface is successional, when two points are close to each other, their temperature is nearly equal. So the new method neglected the temperature difference and incorporated the adjacent elements in one group. After incorporation, the size of cooling model was reduced. The average temperatures of elements in one group were solved firstly. Using these temperature results, the temperature of every element in one group would be computed in the next step. In this way, one large size equations was decomposed into several small size equations. The computational work was reduced and the calculating time was less than one quarter of the conventional method.On the other hand, element incorporation reduced the size of data and helped to weaken the effect of truncation error which caused distorted results. This could enhance the treatable number of element one time more than that of original method.

摘要： 在用边界元方法进行注塑冷却分析时，形成的矩阵方程为满阵，当单元数目超过一定值时，计算机则变得无能为力.针对这一问题，本文介绍一种新的计算方法，首先将单元分组，求出组内单元的平均温度，再利用得到的结果进一步计算组内每一个单元上的温度.采用这种方法，能够有效缩短计算时间，使计算时间仅为常规方法的1/4甚至更少.另外，通过单元合并减少了计算的数据量，改善了因计算机截断误差积累导致计算结果异常的情况，使得冷却分析能处理的单元数目较常规方法提高1倍以上.