1. The facts which can enhance the energy absorption capacity were provided, including the impact section, impact velocity and initial geometrical imperfects.
总而言之，冲击作用横截面、冲击速度、圆管初始几何缺陷等是能够帮助提高能量吸收能力的影响要素。
2. imperfects
2. Methods: 1. Three deerskins (drown on 7 mm × 7mm square reseaus) was pegged on the board by thumbtack. Then line scar and imperfects of rhomboid or rounded were made in the deerskins.
方法：1.将鹿皮（标有7mm×7mm正方形网格）固定于木板上，然后在网格上分别设定线性疤痕、菱形或圆形缺损。
3. The imperfects of existed optimization methods for cutting data are overlaborate procedure and time consuming, and it is difficult to meet all kinds of requirements in modern manufacturing system.
目前，已有的切削数据优化方法存着计算步骤繁复、优化时间长等缺点，难以满足现代制造技术发展的需要。