多层压配组合冷挤压凹模疲劳强度优化设计

采用疲劳强度设计理论和最优化设计理论相结合的方式探讨多层压配组合冷挤压凹模的更为合理、有效的设计方法 .首先 ,推出了 3层压配组合冷挤压凹模在压配状态和工作状态下凹模各层的应力计算公式 ,论证了凹模的疲劳强度校核点在凹模各层的内表面上 ;在此基础上 ,用 Sines法将凹模各层的多向脉冲循环应力等效地转化为单向循环应力 ,并建立了 3层压配组合冷挤压凹模疲劳强度优化设计的数学模型 .用算例进行了优化设计 ,获得了令人满意的结果

Fatigue Strength Optimum Design of Multi-Layer Press-Fit Composite Cold Extrusion Concave Die

It is well known that the rational design of multi layer press fit composite cold extrusion concave die is an effective method of increasing the load capacity, extending the life, and saving the material of a cold extrusion concave die. The key of the rational design is to determine appropriately the constructional dimensions and pre pressure forces between two adjoining layers. According to these, this article developed a new design method of this kind die by combining fatigue design theory and optimum method. First, the article puts forward calculating formulae of stress for each layer in a three layer die under the press fitted and loading situation. Then it proves that the checkpoint of fatigue strenght design is on the inner surface of each layer of the concave die. Based on these results, the article could convert equivalently the multiaxial pulsating repeated stresses of each layer of the concave die to uniaxial repeated stress by means of Sines' method. In addition, the paper establishes a fatigue strength optimum design mathematical model of a three layer die, then applies it to a numerical example and gets a satisfying optimum result.