The failure of the low-voltage wiring harness in the vehicle crash condition includes two types of cutting and extrusion. The cutting failure is mainly caused by the point-surface contact or the line-surface contact between the sharp edge of the part and the wire harness, which causes the wire harness to be cut or even cut off; the extrusion failure is mainly caused by the part squeezing the wire harness along the collision direction, resulting in damage to the insulation of the wire harness and the metal wire part. exposed. The cutting risk is mainly avoided through pre-arrangement design. According to the type of contact, the extrusion form is simplified into three types, that is, three types of extrusion heads are selected: M10 bolt, 5 mm steel sheet, and 20 mm steel sheet, which represent small-area circles respectively. Surface contact, narrow surface contact and wide surface contact.