摘要:
压力容器、桥梁结构、海洋工程结构等在服役过程中经常会在弯曲应力作用下发生失效,因此,研究上述结构的材料或构件在弯曲应力作用下的力学行为具有重要意义。悬臂弯曲加载方式不仅可以产生一个弯曲应力,而且可以通过调长力臂长度,使得只须在试样施力端施加一个很小的力,就能够在试样的最大弯矩附近产生一个甚至可以超过材料屈服强度的应力,对试验机的载荷容量要求不高,因此,在试验领域应用前景广阔。本文根据悬臂弯曲加载方式的特点,从试样的施力端夹具、约束端夹具、力臂调节装置、试验机作动器抗偏心能力、机架刚性等方面进行分析、探讨和设计,并以10CrNiMo结构钢为研究对象,介绍了在该加载方式下的试验应用,包括材料及构件的高低周疲劳、低周疲劳表面裂纹扩展速率,以及材料及构件的静态拉伸或压缩性能等试验。
关键词:
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悬臂弯曲加载
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试验机
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设计
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应用
Abstract:
The pressure vessel,bridge structure and marine engineering structure often fail during service under the bend stress,therefore,it is of significance to study the mechanical properties of the materials or components of above structures under bend stress action. By adjusting the length of force-arm of the specimen under cantilever bend loading,a stress even higher than yield strength of materials could be produced near the maximum bending moment when a small force is exerted on the loading end of the specimen which has made the fatigue test machine under this loading style very popular in the field of test. In this paper,clamps at loading end and limiting end of the specimen,adjusting device for force-arm of the specimen,actuator's capability against eccentricity of the test machine and rigidity of the test machine frame were analyzed,designed and discussed according to the features of the cantilever bend loading. Taking 10CrNiMo structural steel as a research object,some test applications by this loading method were introduced,including high and low cycle fatigue,surface crack propagation rate of low cycle fatigue,and static tension or compression tests of materials and components.
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