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定量研究了Marx法测量低内耗试样内耗及模量亏损时各种粘结剂引起的所谓操作效应。对于水杨酸苯酯,水玻璃混合剂之类弱粘结剂所造成的背景内耗既不能忽略也不是常数,它与粘结层温度、热应力、时间、干燥程度和应变振幅等因素有关。经过高温热循环,粘结剂中出现徽裂缝时呈现双共振峰。在稍高频率的反常共振峰所测得的内耗,随应变振幅或大振幅激发时间的增加而减小,并且在小振幅时效中增大。当反常共振峰频率与正常共振峰靠近时,在内耗-振幅或内耗-时间图上呈现峰值效应。观察到各种共振振幅-频率滞后回线,在一定非线性回线和时效场合下观察到可重复的试样振幅的概周期跳动。采用高温高强度粘结剂后,上述现象均消失,但是热应力使石英传递棒开裂或试样范性变形。分析了Marx法的适用范围及改进途径。
The so-called operational effect caused by various binders when using the Marx method to measure the internal friction loss and the modulus loss of the low-internal-loss specimen was quantitatively studied. The background internal friction caused by weak binders such as salicylic acid phenyl ester and sodium silicate mixture is neither negligible nor constant. It is related to the temperature, thermal stress, time, degree of dryness and strain amplitude of the adhesive layer. After high-temperature thermal cycling, cracks appear in the binder double resonance peak. The internal friction measured at a higher frequency of anomalous formants decreases with increasing strain amplitude or large amplitude excitation time and increases with small amplitude aging. When the frequency of anomalous formant is close to the normal formant, the peak effect appears on the internal friction - amplitude or internal friction - time plot. A variety of resonant amplitude-frequency hysteresis loops were observed. The almost periodic jitter of repeatable sample amplitude was observed under some nonlinear looping and aging conditions. The use of high temperature and high strength adhesive, the phenomenon disappeared, but the thermal stress cracking of the quartz rod or specimen sample deformation. The application of Marx law and its improvement are analyzed.