干湿循环下基于Wiener退化的水泥基复合加芯墙板寿命预测

西部大部分地区干旱少雨、昼夜温差明显,保温墙板处于恶劣环境地区就会产生局部应力集中导致出现裂纹从而缩短服役寿命.设计干湿循环加速试验,通过测试力学性能,微观观测内部结构演变,测定相对质量和相对动弹性模量进行雷达分析和数值回归,最后基于Wiener模型预测试样的可靠度,综合分析干湿循环加速作用下水泥基复合加芯墙板的性能退化规律.结果表明:随着干湿循环加速试验的持续进行,强度呈现增大的状态,抗压强度达到42.5 MPa,抗折强度9.5 MPa;微观结构内部反应产生较多的沉淀CaCO₃逐渐从较密实向松散发展;评价参数都从1开始增大又减小,但整体上呈降低趋势,质量损失率相对于动弹模量敏感度较低,关联度较高;经过回归模型分析,评价指标满足多项式函数的变化规律,可靠度分析质量损失、动弹性模量的工作寿命分别为4 500、3 500 d.

Life prediction model of cement-based composite cored wallboard based on Wiener degradation under dry-wet cycles

Most areas in the west are dry and rainless, the temperature difference between day and night is obvious. When the thermal insulation wall panel is in a harsh environment, local stress concentration will occur, which will lead to cracks and shorten its service life. The wet-dry cycle accelerated test was designed, the mechanical properties were tested, the internal structure evolution was observed, and the relative mass and relative dynamic elastic modulus was measured for radar analysis and numerical regression. Finally, based on Wiener model, the reliability of samples was predicted, and the performance degradation law of cement-based composite cored wallboard under wet-dry cycle accelerated was comprehensively analyzed. The resultsshowed thatthe strength increases with the continuous acceleration test of wet-dry cycle, and the compressive strength reaches 42.5 MPa and the flexural strength reaches 9.5 MPa. The internal reaction of microstructure produces more precipitated CaCO₃, and gradually develops from denser to looser. The evaluation parameters initial increase from 1 and then decrease , but the overall change state is a decreasing trend, and the mass loss rate has a low sensitivity and a high correlation degree relative to the dynamic modulus. Through regression model analysis, the evaluation index meets the changing law of polynomial function, and the working life mass loss and dynamic elastic modulus by reliability analysis is4 500 d and 3 500 d, respectively.