Session: 01-02-01: Adaptive and Multifunctional Structures

Paper Number: 137679

137679 - On Maintaining Bistability of Prestressed Laminates After Clamping 

Bistable composite laminates exhibit a high degree of shape change and stiffness variation between their stable configurations, making them suitable for applications in morphing structures and energy harvesting. However, integration of these laminates into larger systems often imposes different boundary conditions, which can eliminate one of their stable states. Moreover, clamping one or more edges of a rectangular bistable laminate causes a drastic change in its strain energy landscape, indicating a strong interplay between the laminate geometry, boundary conditions, and prestress. In this work, we investigate the effect of clamping on the bistability of rectangular prestressed laminates. An analytical approach is proposed to examine the deflection decay imposed by the boundary condition along the laminate’s length. Different prestress values, laminate dimensions, and material properties are analyzed to establish their effect on the curvature change due to the localized clamp effect. A length criterion is determined to guarantee bistability after clamping the bistable laminate, suggesting the need to utilize complementary techniques to retain the bistable behavior for orthotropic prestressed laminates. Different strategies to counter the clamped edge effect and thereby retain the bistability of these types of laminates are then examined. The proposed analytical model is expanded to consider multi-section composite laminates, showing the role of the symmetric regions in bistability retention. Finally, the results from the model are validated against experiments with good agreement.

Presenting Author: Karthik Boddapati Purdue University

Presenting Author Biography: Karthik Boddapati is a graduate student in the School of Mechanical Engineering at Purdue University. He works in the Programmable Structures Lab (PSL) under the guidance of Dr. Andres Arrieta. Karthik received his bachelor’s degree in mechanical engineering from the Indian Institute of Technology (IIT) Hyderabad, India, in 2019 and a master's degree in mechanical engineering from Purdue University in 2022. Karthik’s research interests include morphing structures, finite element analysis, and multistable mechanisms. Outside of work, he enjoys cooking, traveling, and adventure activities.