<p>As the supporting structure connecting the upper and lower blade shell of wind turbine blades, the function of the blade web plate bears massive shear loads. The traditional sandwich structure of web plates, composed of glass fiber composite panels and polyvinyl chloride (PVC) foam cores, is prone to brittle fracture, exhibiting sudden catastrophic failure with limited energy absorption under long-term cyclic loading. Therefore, developing web plates with high toughness is a critical pathway to prevent brittle fracture during the operation of wind turbine blades. In this study, web plate based on polylactic acid carbon fiber (PLA + CF) material with a triply periodic minimal surfaces (TPMS) structure was designed. Static four-point bending test showed that, the web plates achieve an enhancement in toughness while maintaining sufficient strength compared with the traditional structure. To identify the damage modes of the novel web plate, acoustic emission damage identification method based on stress wave was applied in the static four-point bending test. The research results indicate that the novel web plate predominantly exhibits low frequency acoustic emission (AE) signals, corresponding to numerous matrix cracking and minor fiber/matrix delamination; in contrast, the traditional web plate is dominated by high-frequency signals, leading to through matrix cracking and significant fiber-matrix separation. The frequency difference reflects a transition from catastrophic brittle failure (in traditional web plate structures) to progressive damage (in the novel web plate structure).</p>