Analysis of the displacement amplification ratio of bridge-type mechanism

• A concise and reliable formula is derived based on elastic beam theory.
• The influence of structural dimensions is deeply analyzed.
• The comparisons among different methods have been taken.
• The influence of geometric nonlinearity is also well analyzed.

In order to further understand the characteristics of displacement amplification of bridge-type mechanism, specific analysis is presented in this paper. The average ideal displacement amplification ratio during the deformation process is obtained based on the kinematics theories. Elastic beam theory is adopted to analyze the deformation of the hinges, and a novel formula of theoretical displacement amplification ratio is carried out. A conclusion is reached that the displacement amplification ratio is not related to the material and thickness of structure. Moreover, this conclusion is verified by finite element method. The relationship between displacement amplification ratio and the structural dimensions is analyzed in depth. After the comparisons with existing methods, the formula obtained by elastic beam theory in this paper is proved to be more reliable. And this conclusion is confirmed by the comparison with previous experiment. Furthermore, the influence of geometric nonlinearity of bridge-type mechanism is also well analyzed.