【摘要】 以自行车上零部件——鞍管为例,针对低频载荷,采用鞍管疲劳试验机,对含相同初始裂纹的鞍管进行了疲劳实验,重点考察了负载频率对自行车零部件疲劳寿命的影响。采用弹、粘塑性理论对其进行了理论上的探讨。实验结果和理论分析所得到的结果一致。结果表明:加载频率较大时,裂纹扩展速率较小,导致其疲劳寿命(承受循环载荷的次数)较大,中途改变负载频率时,裂纹扩展速率发生不连续跳跃,随着负载的继续,裂纹扩展速率趋近于变化后的恒定频率下的值。更多还原

【Abstract】 The effect of the loading frequency on the fatigue life of the saddle pillar of a bicycle is investigated.Experimental tests are performed by using fatigue test machine for the saddle pillar.The loading frequency is low and different loading frequencies are selected for test to assess the effect of the loading frequency on the fatigue life.An elasto/visco-plastic theory is utilized to analyze the effect theoretically.The experimental results are in good agreement with the theoretically analysis.It is concluded that as the loading frequency increases,the crack growth rate decreases and the fatigue life (cycle loading times endured) increases accordingly.When the frequency changes from one to another,there is a jump in crack growth rate,and as the load continues,the crack growth rate tends to be the same as the rate under the subsequent frequency.更多还原