Date of download: 12/15/2017 Copyright © ASME. All rights reserved. From: Bistable Compliant Mechanisms: Corrected Finite Element Modeling for Stiffness Tuning and Preloading Incorporation J. Mech. Des. 2012;134(8):084502-084502-6. doi:10.1115/1.4006961 Figure Legend: Configuration and definition of geometry parameters of the bistable straight-guided buckling beams (left half) for (a) case I and (b) case II. The beams have a very small curvature (1/R); the end tips are fixed at an initial angle (θ(r)); in the center (right at the figure) the beams are constraint in x-translation and rotation about z-axis; for preloading effects (case II) the beams are preloaded over a distance (u) along the x-axis; the beams are loaded with a y-displacement (δ) in the center.

Date of download: 12/15/2017 Copyright © ASME. All rights reserved. From: Bistable Compliant Mechanisms: Corrected Finite Element Modeling for Stiffness Tuning and Preloading Incorporation J. Mech. Des. 2012;134(8):084502-084502-6. doi:10.1115/1.4006961 Figure Legend: Deformated shape of the bistable straight-guided buckling beams for case II: with initially straight beams (without curvature) the deformed shape converged into a higher buckling mode (dotted); with a small curvature in the initial beams the deformed shape has the right solution (dashed)

Date of download: 12/15/2017 Copyright © ASME. All rights reserved. From: Bistable Compliant Mechanisms: Corrected Finite Element Modeling for Stiffness Tuning and Preloading Incorporation J. Mech. Des. 2012;134(8):084502-084502-6. doi:10.1115/1.4006961 Figure Legend: Typical behavior of the force–displacement characteristic of a bistable mechanism; point a is the first stable point; at point b, the force exerted on the mechanism is at its maximum; point c is the unstable equilibrium position, where the bistable mechanism snaps and produces a force in the same direction as the travel range; this force is the largest at point d; point e is the second stable position of the beams; the area of the curve for Fpos and Fneg is the energy needed to put in the mechanism (Ein) or the energy produced by the mechanism (Eout), respectively

Date of download: 12/15/2017 Copyright © ASME. All rights reserved. From: Bistable Compliant Mechanisms: Corrected Finite Element Modeling for Stiffness Tuning and Preloading Incorporation J. Mech. Des. 2012;134(8):084502-084502-6. doi:10.1115/1.4006961 Figure Legend: Flow chart of the subsequent transient analysis; the data of the preloaded initial shape (time interval 1) are used to solve the analysis for the deformed structure (time interval 2); the data of the deformed structure together with the prescribed displacement give the final results

Date of download: 12/15/2017 Copyright © ASME. All rights reserved. From: Bistable Compliant Mechanisms: Corrected Finite Element Modeling for Stiffness Tuning and Preloading Incorporation J. Mech. Des. 2012;134(8):084502-084502-6. doi:10.1115/1.4006961 Figure Legend: Top view of the measurement set-up: The force–displacement characteristic of mechanisms was determined by measuring actuation force (Fact) and displacement (Xact) from relaxed position to the second stable position and vice versa; the angle and preloading were adjusted by a rotational stage mounted on a linear stage

Date of download: 12/15/2017 Copyright © ASME. All rights reserved. From: Bistable Compliant Mechanisms: Corrected Finite Element Modeling for Stiffness Tuning and Preloading Incorporation J. Mech. Des. 2012;134(8):084502-084502-6. doi:10.1115/1.4006961 Figure Legend: Results of the experiments and the ANSYS™ simulations for three typical cases: (1) with initial curvature (solid), (2) without initial curvature (dashed), (3) with initial curvature and preloading (dotted)

Date of download: 12/15/2017 Copyright © ASME. All rights reserved. From: Bistable Compliant Mechanisms: Corrected Finite Element Modeling for Stiffness Tuning and Preloading Incorporation J. Mech. Des. 2012;134(8):084502-084502-6. doi:10.1115/1.4006961 Figure Legend: Results of the evaluation ratios determined with ANSYS™ analysis for varying the preloading in case II, normalized to the largest value of each ratio