MB8变形镁合金超声疲劳试样解析设计

Design of Ultrasonic Fatigue Specimen of MB8 Wrought Magnesium Alloy by Analytic Method

对MB8变形镁合金超声疲劳试样进行设计计算。为了减小试样振幅,使试样产生较少的热量,减轻冷却系统压力的同时防止试样产生相变等组织变化,将试样设计成变截面形状。根据试样振动位移方程、边界条件和位移连续条件推导出试样谐振长度与其他尺寸的关系,计算出一系列超声疲劳试样的尺寸。结果表明:变截面圆柱和板状试样随着圆弧过渡段长度增大,谐振长度减小,圆弧过渡半径增大;对于无中间等截面段试样,位移应力系数Cs和应力放大系数M随着圆弧过渡段长度减小而减小;对于含有中间等截面段试样,位移应力系数Cs和应力放大系数M随着中间等截面段长度减小而减小。

Ultrasonic fatigue specimen of MB8 wrought magnesium alloy was designed by calculation. In order to reduce the vibration amplitude,heat and pressure of the cooling system and also to protect the phase change,the sample was designed into variable crosssection. Based on the vibration displacement equation,boundary condition and displacement continuity condition,the relationship between the resonant length and other dimensions of the sample was derived. A series of size of ultrasonic fatigue specimens was calculated,which provided reference for the research of ultrasonic fatigue test of magnesium alloy. The results show that the resonance length decreases with the increase of the length of transition section,and the arc transition radius increases with the increase of the length of arc transition section. With the decrease of the length of arc transition section,Cs and M decreases for the specimen without uniform cross section in middle. With the decrease of the length of uniform cross section in the middle,Cs and M decreased for the specimen with uniform cross section in the middle.