英语语法分析

This paper tells the calculation and test results of the rigidity and strength of all-closed large underframes on depressed centre flat cars D18A. Several problems concerned are analyzed.

本文介绍了D_（18A）型凹底平车全封闭式大底架结构刚度、强度的计算和试验结果，对与此有关的若干问题进行了分析。