刨头间隙碰撞载荷下滑架体疲劳寿命试验分析

Fatigue life test analysis of sliding framework under clearance impact load of plough

针对刨煤机中部槽滑架体在工作过程中出现的疲劳断裂现象,采用理论与试验相结合的方法,基于Winkler弹性地基接触模型,建立了刨头三自由度碰撞振动动力学模型.通过点到直线的距离算法作为检验碰撞的准则,构造了刨头与滑架接触碰撞判别条件.采用数值方法进行求解,得到刨头与滑架各点的最大碰撞力,并以此作为疲劳试验载荷,对中部槽滑架体进行疲劳寿命试验,得到了滑架体的疲劳寿命.研究结果表明:滑架体在最大碰撞力作用下,在立板前端产生初始裂纹,在发生静强度失效时,失效点倾向于立板后部下端.研究结果对提高滑架体疲劳强度提供了理论依据.

To solve the fatigue break phenomenon on the middle part of sliding framework of coal planer happened during the working process, the 3-DOF crash dynamic model of plough was established based on the Winkler model by combining theory and experiment together. Test criterion of contact-impact between plow head and sliding framework was established by the collision detection method of the arithmetic of the distance between a point and a line. The maximum impact forces of plow head and sliding framework on each point were obtained by numerical methods,and were used as the load of fatigue test. The fatigue test of middle trough sliding framework was executed. Fatigue life of sliding framework was obtained. The results showed that initial crack appeared at the forepart of standing plate when sliding framework was under the maximum impact force and the failure point tended to appear at the bottom of standing plate when static strength became invalid. The results provide theoretical basis for the improvement of fatigue strength of sliding framework.