不同碳纤维布加固方式的木构件损伤演化规律

Damage Evolution Law of Wooden Components Reinforced with Different CFRP Reinforcement Methods

为研究不同碳纤维布(CFRP)加固方式时木构件的损伤演化规律,有效评估构件的损伤程度,利用声发射、数字图像技术对碳纤维布加固的杉木构件在轴向压缩时的损伤过程进行实时监测。分析了不同加固方式对木构件的力学特性、声发射参数、表面应变场演化特征的影响。结果表明:碳纤维布的加固能明显改善木材的力学性能,抑制脆性破坏的发生,随着加固层数、角度的增大,木材的平均极限承载力、位移延性随之增大;声发射信号的活跃程度随着碳纤维布加固的角度、层数的增大逐渐降低,累计振铃计数、累计能量值也随之减小,利用数字图像技术可以有效观测裂纹的萌生及扩展方向,两种方式结合可以全面揭示木材的内部损伤程度以及裂纹演化规律;通过声发射法、数字图像法可以确定不同加固方式时试件的起裂荷载,随着加固角度、层数的增大,起裂荷载也逐渐增大;根据声发射累计事件数与荷载关系建立的损伤演化模型,可以较好地反映材料在轴压过程中的损伤演变规律。

To study the damage evolution of wooden components reinforced with different carbon fiber reinforced polymer(CFRP)reinforcement methods and effectively evaluate the extent of damage,real-time monitoring of the damage process of spruce wooden components reinforced with carbon fiber fabric under axial compression was conducted using acoustic emission and digital image techniques.Analyzed the effects of different reinforcement methods on the mechanical properties,acoustic emission parameters,and surface strain field evolution characteristics of wooden components.The results showed that CFRP reinforcement significantly improved the mechanical performance of wood,suppressing the occurrence of brittle failure.With the increase in the number of reinforcement layers and angles,the average ultimate bearing capacity and displacement ductility of wood increased.The activity level of acoustic emission signals gradually decreased with the increase in the angle and number of CFRP reinforcement,and the cumulative ringing count and cumulative energy value also decreased.The digital image technique effectively observed the initiation and propagation direction of cracks.The combination of these two methods comprehensively revealed the internal damage extent and crack evolution characteristics of wood.The initiation load of specimens under different reinforcement methods could be determined using the acoustic emission and digital image methods.With the increase in the reinforcement angle and number of layers,the initiation load gradually increased.The damage evolution model established based on the relationship between cumulative acoustic emission events and load could well reflect the damage evolution law of materials during axial compression.