ABSTRACT

This article examines the performance of an existing log truck cab guard subject to impact from the load of logs shifting forward during sudden truck deceleration, and considers modifications to the cab guard to reduce the effect of impact. It was found that the logs impacted the existing cab guard with a load sufficient to reach the design displacement of 0.25 m and to exceed the yield stress in the foot and in the gusset for log truck decelerations greater than 32.5 m/s². Increasing the cross section of the cab guard foot reduces the maximum stress found in the foot; however, this resulted in the maximum stress in the gusset increasing from the original design. Increasing the gusset thickness resulted in a slight decrease in the maximum stress found in the gusset, with little change in the maximum stress found in the foot. Increasing the yield stress of the steel did not change the stress distribution; however, this did result in the maximum stress found in the foot being below the new yield stress. Adding an energy absorbing pad to the cab guard improved all the performance metrics resulting in the maximum stress in the foot being well below the original yield stress, reducing the maximum stress in the gusset to near the yield stress, and reducing the displacement by almost a third.

摘要

本文检查了现有的原木卡车驾驶室防护罩在卡车突然减速期间受到向前移动的原木负载的冲击的性能，并考虑对驾驶室防护罩进行修改以减少冲击的影响。发现原木以足以达到 0.25 m 的设计位移的载荷冲击现有的驾驶室护板，并超过脚部和角撑板中的屈服应力，以便原木卡车减速大于 32.5 m/s ². 增加驾驶室护脚的横截面可减少在脚上发现的最大应力；然而，这导致角撑板中的最大应力比原始设计增加。增加角撑板厚度会导致角撑板中的最大应力略有下降，而足部的最大应力几乎没有变化。增加钢的屈服应力并没有改变应力分布；然而，这确实导致足部的最大应力低于新的屈服应力。在驾驶室护板中添加吸能垫改善了所有性能指标，导致脚部的最大应力远低于原始屈服应力，将角撑板中的最大应力降低到接近屈服应力，并将位移减少近第三。