ABSTRACT

High impact shovel loading operations expose the truck operators to whole body vibrations (WBV), exceeding the ISO exposure limits resulting in long term disabilities and health issues. With dynamic force resulting from the gravity dumping of material during each shovel pass being the main cause for these high frequency shockwaves, this work focused on developing a robust mathematical model, using Lagrangian mechanics, for capturing and examining the force on truck surface during multi-pass shovel loading process. The model was tested through experiments for the case where a CAT 793D dump truck was loaded by a large capacity P&H 4100 XPC cable shovel. Maximum impact force amplitudes of 692 kN and 622 kN, were recorded for the first and second shovel passes, respectively. Moreover, a cushioning effect of 10.12% was observed during the second shovel pass, which significantly reduced the impact on the truck bed surface. With such deeper understanding of generation and propagation of the impact force, solutions can be developed to eliminate, or at least reduce, the force magnitudes to keep them within appropriate levels. This work will serve as a stepping stone towards the development toof technologies to enhance the health and safety of truck operators.

摘要

高冲击铲装载操作使卡车操作员暴露于全身振动 (WBV)，超过 ISO 暴露限制，导致长期残疾和健康问题。由于每次铲运过程中物料的重力倾倒产生的动态力是这些高频冲击波的主要原因，因此这项工作的重点是开发一个强大的数学模型，使用拉格朗日力学，用于捕获和检查卡车表面上的力。通过铲装载过程。该模型通过对 CAT 793D 自卸车装载大容量 P&H 4100 XPC 电缆铲的情况进行了实验测试。分别记录了第一次和第二次铲运的最大冲击力振幅为 692 kN 和 622 kN。此外，缓冲效果为10。在第二次铲运过程中观察到 12%，这显着降低了对卡车底板表面的影响。随着对冲击力的产生和传播有了如此深入的了解，可以开发解决方案来消除或至少减少力的大小，以将它们保持在适当的水平。这项工作将成为开发技术以提高卡车操作员的健康和安全的垫脚石。