摘要
为了建立有效的基于弹性波的螺栓连接损伤检测方法,研究弹性波在连接结构中的传播行为至关重要。本文针对典型单螺栓搭接薄梁,采用非线性多物理场耦合有限元仿真方法,研究弹性波在连接结构中的传播行为。采用ANSYS中压电耦合单元建模MFC压电传感器,非线性接触单元建模螺栓连接结构,将接触面之间考虑为考虑摩擦接触的非线性关系。依次对螺栓施加预紧载荷,对结构施加模拟电压激励,进行非线性瞬态波传播分析。同时,本文对仿真结果进行了实验验证。结果表明,本文建立的有限元模型和分析方法能够有效地模拟弹性波在连接结构中的传播过程,数值预测的响应电压和实验结果吻合较好。针对非线性模型计算耗费大的问题,本文对非线性模型进行了线性化改进。具体为采用准静态接触有限元分析确定对接面有效接触面积的大小,然后将接触面积上对应节点绑定,进行线性瞬态波传播分析。结果表明:本文的线性方法能够有效模拟波传播过程,并能有效降低计算耗费;弹性波在连接梁中传播时,经过连接界面和螺栓位置时,传播路径、波形、幅值都发生了较大的变化。
Following a severe loading condition, bolted joints in assembled structures can loosen or fail. Health monitoring method based on elastic wave propagation is regarded as an efficient way to detect bolt looseness damage. To establish an efficient bolt looseness damage detection method based on elastic wave, it is primary to understand how elastic wave propagating in bolted structures. In this paper, a lap-jointed beam is modeled with nonlinear coupled field FEM method, to study wave propagation in bolted structures. MFC transducers are modeled with coupled field elements, the contact surfaces are modeled with contact pairs. The results show that the nonlinear model built in this paper can simulate wave propagation in bolted structures properly; the simulation results match well with actual experimental signals. The nonlinear model is computationally costly to use for parametric or optimization studies, for this reason, a simplified linear model is built. A preliminary static analysis is conducted to determine the contact area, then nodes on the entire contact surface are bonded. The results show the linear model in this paper can simulate wave propagation in bolted structures properly too, and also can reduce computation costs. The propagation path, wave form and wave amplitude change a lot when wave propagation through bolted joints.
出处
《应用力学学报》
CAS
CSCD
北大核心
2018年第3期458-464,共7页
Chinese Journal of Applied Mechanics
基金
国家自然科学基金(11372246)
CAST-BISEE基金
