Mech. Sci., 6, 155–161, 2015 www.mech-sci.net/6/155/2015/ doi:10.5194/ms-6-155-2015 © Author(s) 2015. CC Attribution 3.0 License. Synthesis of PR-/RP-chain-based compliant mechanisms – design of applications exploiting fibre reinforced material characteristics U. Hanke 1 , E.-C. Lovasz 2 , M. Zichner 1 , N. Modler 1 , A. Comsa 1 , and K.-H. Modler 1 1 Faculty of Mechanical Engineering and Machine Science, TU Dresden, Dresden, Germany 2 Department of Mechatronics, Politehnica University of Timisoara, Timisoara, Romania Correspondence to: U. Hanke (uwe.hanke@tu-dresden.de) Received: 28 November 2014 – Revised: 18 May 2015 – Accepted: 8 July 2015 – Published: 25 August 2015 Abstract. Compliant mechanisms have several advantages, especially their smaller number of elements and therefore less movable joints. The flexural members furthermore allow an integration of special functions like balancing or locking. Synthesis methods based on the rigid body model (Howell, 2001; Sönmezv, 2008) or topology optimisation (Zhou and Mandala, 2012) provide practical applications from the advantages of com- pliant elements. Beside these methods, a much simpler approach is the geometric-based synthesis (Ehlig et al., 2013) which is focused on solving guidance tasks by using RR-chain 1 -based compliant linkages. More compact compliant linkages can be build up by using only PR 2 or RP 3 chains. Therefore a tool is needed to extend the RR-chain-based approach. The necessary analysis of the compliant beam element can be done by numerical analysis and through experiments. Due to the validity of the Bernoulli beam model the elastic similitude can be specialised and a more general synthesis of compliant beam elements can be created. Altogether a generalised synthesis method can be created for handling different linkage structures as well integrating beam elements de- rived numerically or by measurement. The advances in this method are applied in the synthesis for a cupholder mechanism made of fiber reinforced material. 1 Introduction Classical linkage structures need additional elements (e.g. springs) for balancing or locking, which gives rise to the structure complexity. These features can be directly imple- mented by using compliant linkages. This function integra- tion used in a compliant cupholder mechanism (Ehlig et al., 2013) lead to a simple two part assembly (RR chain coupled to a beam element (B ): RRB mechanism; Fig. 1). The in- tegrated compliant section allows for the implementation of locking so that additional springs are not required. The ap- plied geometric-based synthesis method allows for its direct 1 one link with two rotational joints (R) 2 one link with one frame fixed prismatic joint (P) and one mov- ing rotational joint (R) 3 one link with one frame fixed rotational joint (R) and one mov- ing prismatic joint (P) use in the design process, providing maximum design free- dom regarding position and size of the mechanism. Much simpler mechanisms can be derived by introducing P joints. The intermediate link can be completely eliminated. Hence for assembling such near monolithic mechanism only one bolt (R joint) is needed. To make use of this advantage, the synthesis of compliant mechanisms has to be extended to P joints. The advantage of the geometric method should form the basis when implementing RP/PR chains. Specialising the similitude theory provides additional ben- efits in deriving a set of compliant beam elements and in the direct use of experimental data for the mechanism synthesis. 2 Synthesis The compliant beam section B 0B of the mechanisms shown in Fig. 1c is integrated in the guidance link AB and acts like a spring element. For the synthesis model, the large deflections Published by Copernicus Publications.