Experimental Verification Of Large Deflection Post-buckling Theory

The actuality of domestic and international developments of the bistable structures is introduced. The critical transverse force for the arch beam to snap is obtained by utilizing the small deflection theory and the variational principle, and meanwhile the correctness of the deduction can be validated by FEA methods. The nonlinear relations between the transverse forces and the geometrical dimensions of different kinds of bistable micro-structures are given by using the ANSYS software while the micro-beams deflect in small dimensions. For large deflection buckling beam-structures, an digital electrical testing platform is designed to validate the theory deductions of mechanics of the oblique braced beams. The material of the testing beams is be-bronze. Large amount of effective data is obtained while the oblique braced beams with different initial angles and length deflect largely. Comparing with the results of experiments, the correctness of the theoretical analysis is validated. Therefore, we can conclude that analyzing theory for large deflection post-buckling beams deduced by authors of related references is correct and effective.Based on the large deflection buckling theory and effective testing datum, results from the transverse force computation formula get a well agreement with those from experiments, which indicate an obvious bistable effect during the deformation process of the oblique braced beams. The transverse force increases quickly with the displacements of the beam tip. While the beam tip exceeds the critical position and the beam buckles, the transverse force decreases with the increase of the tip displacement until the beam achieves the second stable position. So the formulas of the large deflection post-buckling beams derived by the authors of Xidian University can be used in designing bistable micro-switches.