木基复合材料破坏过程中声发射特性的研究

利用声发射监测系统获取了胶合板和贴面刨花板两种木基复合材料三点弯曲加载状态下断裂损伤的声发射信号。利用累计能量和振铃总计数两项声发射信号特征参量分析了胶合板和贴面刨花板损伤破坏过程及其特点;利用幅值和有效电压（RMS）研究了随挠度增大胶合板和贴面刨花板内部裂纹产生、扩展、宏观裂纹形成至断裂的过程。结果表明:声发射信号的幅值、有效电压、累计能量、振铃总计数等参量可以有效表征木基复合材料内部损伤演化过程;贴面刨花板的断裂损伤发生早于胶合板,且贴面刨花板的损伤演化过程分为线弹性阶段和断裂韧性阶段,胶合板分为线弹性阶段、非线性变形阶段和断裂韧性阶段。

Acoustic emission characterization of wood base composite materials fracture

Acoustic emission system was used to obtain acoustic emission signals of fracture from plywood and chipboard specimen subjected by three-point-bending.Two acoustic emission signals of cumulative energy and total ring counts were used to discuss the fracture process and characteristics of plywood and chipboard.By using amplitude and RMS,the process of internal fracture formation,crack propagation,appearance of macro-cracks and rupture of plywood and chipboard was discussed with the increase of deflection.The results showed that internal damage evolution of wood-based composites could be effectively characterized by parameters of acoustic emission signals,such as amplitude,RMS,cumulative energies and total ring counts.Fracture damage occurred earlier in chipboard than that in plywood,and damage evolution process of chipboard could be divided into two stages,that of plywood into three stages.