正六边形孔蜂窝钢梁焊缝裂纹损伤监测数值模拟

Weld Crack Damage Monitoring Numerical Simulation on Honeycomb Steel Beam with Regular Hexagonal Holes

钢梁薄弱位置处的裂纹可能会对整体结构安全造成极大危害,为了监测正六边形孔蜂窝钢梁的焊缝裂纹损伤情况,以焊缝带有裂纹的正六边形孔蜂窝钢梁为研究对象,采用Abaqus数值软件,建立了基于压电传感的不同裂纹损伤工况下蜂窝钢梁数值监测模型,研究了压电信号在裂纹损伤蜂窝钢梁数值模型中的影响规律,得到了裂纹长度损伤程度和裂纹深度损伤程度与裂纹损伤指标的关系表达式,明确了不同裂纹工况下应力波在蜂窝钢梁数值模型中的传播过程。结果表明,基于压电传感原理建立了正六边形孔蜂窝钢梁焊缝裂纹损伤监测数值模型,数值模型中采用汉宁窗激励信号及三维黏弹性边界,该边界能够较好地模拟应力波通过裂纹时的衰减效果;随着裂纹长度和深度的增加,压电信号时域幅值会产生不同程度的衰减,且裂纹深度对时域信号的影响较大;裂纹损伤程度越大,裂纹损伤指标值越大,且损伤刚出现时其增长幅度最大,说明应力波传播对裂纹损伤较为敏感;当裂纹长度增大到整个焊缝长度时,压电信号时域幅值衰减了33.3%,且焊缝附近应力减少了37.8%;当裂纹深度增加到整个焊缝厚度时,压电信号时域幅值衰减了95.4%,且焊缝附近应力减少了99.2%,此时传感器接收到的压电信号很小,焊缝附近钢梁接收到的应力波几乎可以忽略不计。

Cracks at weak locations in steel beams can be extremely hazardous to overall structural safety.To monitor the weld crack damage of honeycomb steel beam with regular hexagonal holes,the honeycomb steel beams with regular hexagonal holes with weld cracks was taken as the study object.The numerical monitoring model of honeycomb steel beam under different crack damage conditions based on piezoelectric sensing was established by using Abaqus numerical software.The influencing rule of piezoelectric signals in the crack damage honeycomb steel beam numerical model was studied.The relation expressions among crack length damage degree,crack depth damage degree and crack damage index were obtained.The stress wave propagation processes in honeycomb steel beam numerical model under different cracking conditions were also clarified.The result indicates that the weld crack damage monitoring numerical model of honeycomb steel beam with regular hexagonal holes is established based on the piezoelectric sensing principle.The Hanning window excitation signal and three-dimensional visco-elastic boundary are used in the numerical model.The boundary can well simulate the attenuation effect of stress wave passing through cracks.With the increase of crack length and depth,the piezoelectric signal time-domain amplitude attenuates to different degrees,and the crack depth has greater influence on the time-domain signals.The larger the crack damage degree is,the larger the crack damage index value is.The growth rate is the largest when the damage appears,indicating that the stress wave propagation is sensitive to the crack damage.When the crack length increases to the whole weld length,the piezoelectric signal time-domain amplitude decreases by 33.3%,and the stress near weld decreases by 37.8%.When the crack depth increases to the whole weld thickness,the piezoelectric signal time-domain amplitude attenuates by 95.4%,and the stress near weld decreases by 99.2%.At this time,the piezoelectric signal received by the sensor is tiny,and the stress wave received by the steel beam near weld is almost negligible.