Modeling and Analysis of a Bistable Compliant Mechanism
Compliant mechanisms realize mechanism functions by utilizing the elastic deformations of flexible components rather than the relative motions of rigid joints. The advantages of compliant mechanisms stem from the removal or replacement of rigid joints, which include the elimination of backlash, friction, wear and lubrication, the reduction of vibration and noise, the decreased manufacturing and assembly cost, and the increased precision. Bistable compliant mechanisms have two stable equilibrium positions and have many different applications.
The bistable compliant mechanism in this project is from a double-clamped buckled beam. The initially straight, uniform and horizontal beam has undeformed length, (out-of-plane) width and (in-plane) thickness of 150 mm, 8 mm and 1 mm, respectively. The material for the beam is engineering plastic with Young's modulus of 2000 MPa, yield strength of 60 MPa and Poisson's ratio of 0.45. The left end of the beam is clamped. The right end of the beam is constrained for any rotation and vertical displacement. The right end is first moved to its left by 5 ram to make the beam have its upward buckled shape, and then Clamped. A step-by-step downward displacement of 1 mm is applied to the middle point of the buckled beam to have the beam snap from its upward buckled shape to its downward buckled shape.
Use ANSYS to model the undeformed beam, derive the upward buckled shape, snap the beam from its upward buckled shape to its downward buckled shape. Simulate the snapping process of the buckled beam within ANSYS. Find out the maximum stress within the beam in the snapping process, and the required input force (critical force) for the buckled beam to snap.
Reference- Dews Joy, Hong Zhou, "Analysis and Synthesis of Bistable Compliant Mechanisms using Precompressed Beams," International Journal of Engineering Research and Technology, 2016, 5(7): 325-330.
Attachment:- Assignment.rar