Mode Shapes in Compliant Mechanisms, and a Procedure to Identify Appropriate Pseudo-Rigid-Body Model Type


The mobility characteristics of compliant mechanisms are a function of the structural arrangement of the comprising segments and links, their types, as well as the load and/or displacement boundary conditions. It is hypothesized that an earlier defined concept of compliance number and stored strain energy in a compliant mechanism are strongly correlated. It therefore becomes necessary to define and better understand the characteristics of deformation mode shapes of compliant mechanisms. A compliant mechanism may exhibit a variety of mode shapes. In keeping with the classical mechanics notions, this paper systematically develops the mode shapes in compliant mechanisms, utilizing two distinct categories: i) segmental (elemental) mode shapes, and ii) mechanism (system) mode shapes. The possible mode shapes of the basic segment types are identified. Based on the energy storage capability of the segment types, segmental mode shapes are further classified into higher and lower order mode shapes. Similar identification is extended to compliant mechanisms as well, and the possible mechanism mode shapes are illustrated with the help of a few examples. Finally, the utility of this methodology in identifying an appropriate pseudo-rigid-body model (PRBM) corresponding to a given compliant mechanism is demonstrated. An experimental procedure AIDS in this process.

Meeting Name

ASME 2015 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, IDETC/CIE 2015 (2015: Aug. 2-5, Boston, MA)


Mechanical and Aerospace Engineering

Keywords and Phrases

Design; Mechanisms; Rigid structures; Strain energy; Classical mechanics; Displacement boundary conditions; Experimental procedure; Mobility characteristics; Possible mechanisms; Pseudo-rigid-body models; Storage capability; Structural arrangement; Compliant mechanisms

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Document Type

Article - Conference proceedings

Document Version


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© 2015 American Society of Mechanical Engineers (ASME), All rights reserved.

Publication Date

01 Aug 2015