基于模态应变能的木地板结构损伤识别数值分析

Numerical research on the damage detection of wood floor based on modal strain energy

提出一种全新的鉴定木地板结构损伤的方法,即利用结构的模态应变能前后变化来衡量木地板结构的损伤程度。假定结构存在不同位置和不同程度的损伤,将木地板结构简化成为简支梁,运用有限元软件ANSYS进行模态分析,得到木地板结构损伤前后的前8阶模态,并计算各单元的损伤指标,研究该方法的适应性。试验结果表明:对于单个位置损伤,以低阶模态应变能差值为指标能够准确识别木地板结构的损伤位置与损伤程度,对于多位置损伤,该指标也能给予准确的识别结果。因此,采用低阶模态应变能差值作为损伤指标的方法为木地板结构的损伤识别提供一条可靠的途径。

Modal strain energy is more sensitive to local damage of wood floor structure than natural frequencies. Difference value of modal strain energy is used as damage index. Assume there are different damage positions and extents in wood floor structure, and make the wood floor structure as simple beam, the software ANSYS is applied to obtain the first eight modes of wood floor structure before and after damage, and then every element damage index of the structure is calculated. The numerical results show that low-order modal strain energy change can reflect the location of damage of wood floor structure, and the value of damage index increases along with the increase of damage extents, which can used to identify the extents of damage. It is concluded that the proposed damage index is feasible for the damage identification of wood floor structures.