Abstract— The present paper deals with the study of the mechanical properties of some polymeric composite materials that may be used in manufacturing orthopaedic implants. The first part of the paper concerns theoretical aspects related to the studied composite materials. The second part of the paper deals with the experimental setup used for the materials tests, continuing with the obtained experimental results. The paper ends with the conclusions based on the performed studies and researches. Index Terms— composite materials, implants, compression, bending, mechanical properties. I. INTRODUCTION A very important socio-economic issue of this century is the increasing occurrence of osteoporosis. The most severe complication of this disease is represented by the proximal femoral fracture that considerably contributes to the elder people mortality due to already existing diseases and complications after prolonged bed confinement. The diagnosis and treatment expenses have been growing constantly as a result of new investigation techniques and new implants and instruments used for the internal fixation and joint replacement. One of the most promising possibilities of decreasing these costs is to identify and study new materials that may be used for implants and decide if they correspond both from mechanical and biomechanical point of view. Our attention is focused on some types of polymeric composite materials whose processing and manufacturing involve reasonable costs, in order to determine the suitability of their mechanical properties. II. THEORETICAL ASPECTS The polymeric materials are the most representative class of materials used in the current manufacturing of various technical components and consumer goods. A special place is taken by the composite polymeric materials as a distinct and spectacular proposal for new and effective solutions. Manuscript received March 17, 2010. This work was supported by Grant PNII-IDEI 722 and 744 with CNCSIS Romania. D. Cotoros PhD. is assoc. professor with the Mechanics Department of University Transilvania from Brasov, Romania; e-mail: dcotoros@unitbv.ro ; dcotoros@yahoo.com A. Stanciu is assist.prof. with the Mechanics Department of University Transilvania from Brasov, Romania; e-mail: ancastanciu77@yahoo.com M. Baritz PhD. is professor with Fine Mechanics and Mechatronics Department of University Transilvania from Brasov, Romania; e-mail: mbaritz@unitbv.ro , baritzm@yahoo.com Regarding the mechanical tests meant for the study of polymeric composite materials behaviour we may consider a principle similarity with the tests applied on metals. The differences concern only the shape and size of the test specimens or the magnitude of the applied forces. Most of the conception procedures either simple or sophisticated will be based on data concerning the stiffness and will be connected to the assessment of the deformation or bending limit. As a consequence, the values of Young’s modulus are usually required for the principal directions on both planes using perpendicular axes. Young’s modulus controls the displacement/ deformation within the material. For an isotropic material, the connection between the stiffness parameters, Young’s modulus (E) and transverse elastic modulus (G) is given by (1). G = E/2(1+ v) (1) the equivalent equation for the elastic modulus on both planes G 12 being f f V V 1 1 m 12 G G (2) where m f m f G G G G 12 12 1 (3) and the reinforcement constant ξ’ is 1. This determines different absolute values and also different ratios of the transverse elasticity and tension on both planes. The bending stiffness denoted R for a sandwich type element consisting of thin layers with identical thickness is the result of the addition of the external layers bending stiffness and the core stiffness about the cross-section axes: , 12 2 6 3 2 3 c b E d t b E t b E R c s s (4) where s E and c E represent the Young’s modulus of the layers and respectively of the composite core. If the layers are made of different materials, with different thickness, as the analyzed structure, and assuming that the bending stiffness between the layers can not be neglected, it means that 77 . 5 t d (5) The bending stiffness of the structure can be written as follows: 3 2 2 3 1 1 2 2 1 1 2 1 2 1 2 12 t E t E b t E t E t t E E d b R s s s s s s (6) Experimental Research Concerning Mechanical Properties of Materials for Biomedical Use Diana Cotoros, Member, IAENG, Anca Stanciu, Mihaela Baritz, Member, IAENG Proceedings of the World Congress on Engineering 2010 Vol II WCE 2010, June 30 - July 2, 2010, London, U.K. ISBN: 978-988-18210-7-2 ISSN: 2078-0958 (Print); ISSN: 2078-0966 (Online) WCE 2010