If deceleration is constant in a vehicle crash, deformation of the vehicle is a function of impact speed and impact duration. The ratio of actual deformation to this idealized quantity may be used to summarize the shape and effects of the deceleration pulse. This ratio reflects whether the pulse is front-loaded (acceleration is greater early in the pulse than later), or back-loaded (acceleration is less early in the pulse than later). Further interpretation of the ratio is possible within simple families of pulse shape, such as M. Huang’s TESW (Tipped Equivalent Square Wave) model and the triangular pulse. This paper reviews published test results and summaries of datasets. It is found that pulses tend to be back-loaded. However, this conclusion is sensitive to how deformation, speed, and duration are calculated.

如果在车辆碰撞中减速度恒定，则车辆的变形取决于冲击速度和冲击持续时间。实际变形与该理想量的比率可用于总结减速脉冲的形状和效果。该比率反映了脉冲是前加载的（脉冲中的加速度比后一脉冲的加速度大）还是后加载的（脉冲中的加速度比后一脉冲的加速度小）。在简单的脉冲形状系列中，例如M. Huang的TESW（倾斜等效方波）模型和三角脉冲，可以进一步解释该比率。本文回顾了已发布的测试结果和数据集摘要。发现脉冲倾向于被反向加载。但是，此结论对如何计算变形，速度和持续时间很敏感。