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本文比较详细地阐述了碳化硅纤维增强铝复合材料在加载与恒载下的声发射过程和特征。通过加载试验,发现复合材料的声发射计数率与应力-应变的关系曲线只有指数规律上升的一段,而没有象金属的那种延续段,从而表明复合材料是脆性断裂,同时表明SiC纤维是逐渐地而不是同时地断裂。这正是复合材料强度具有离散性及往往低于ROM计算值的原因之一。 为了研究复合材料的承载强度余量及许用应力的选取,做了恒载下的声发射试验。根据恒载下声发射的收敛性和声发射振铃计数脉冲出现时间间隔不断增长的趋势,判断材料承载强度余量的稳定状态以及验证许用应力选取方法的可取性,同时提出了混合物定则(ROM)的修正公式。
In this paper, the acoustic emission process and characteristics of silicon carbide fiber reinforced aluminum composites under load and constant load are described in more detail. Through the loading test, it was found that the curve of acoustic emission count rate and stress-strain curve of composite had only an exponentially increasing section without any continuation of the metal, which indicated that the composite was brittle fracture and at the same time showed that SiC fiber was gradually Instead of breaking at the same time. This is one of the reasons why composite strength tends to be discrete and often below ROM calculations. In order to study the balance of load-bearing strength of composite materials and the selection of allowable stress, acoustic emission test under constant load was done. According to the convergence of acoustic emission under constant load and the rising interval of ringing counting pulse of acoustic emission, the steady state of material bearing strength margin and the desirability of verifying allowable stress selection method are also proposed. At the same time, the rule of mixture (ROM) correction formula.