International Journal of Scientific Engineering and Technology (ISSN : 2277-1581) Volume No.3 Issue No.8, pp : 1085-1087 1 Aug 2014 IJSET@2014 Page 1085 Modeling and Analysis of Rotating Seal and Friction Damper; Calculation of Damper Stiffness Dipendra Singh, V Suresh Babu, J Srinivasan Email: dipendrabhadauriya0@gmail.com, vsbabu_nitw@yahoo.com , srinivasanj@ge.com Abstract : In this paper modeling of rotating seal and friction damper is explained using NX7.5 and ANSYS130x64 software. Modeling of any component is very important in analysis of the component. Analysis of rotating seal and damper is carried out using ANSYS130x64 to calculate stiffness of friction damper. Various authors explained methods to calculate stiffness of friction damper. In this paper a method is proposed to calculate stiffness of friction damper. Keywords Friction damper, Rotating seal, Damper stiffness and damper circumferential growth INTRODUCTION Frictional forces arising from the relative motion of two contacting surfaces are a well-known source of energy dissipation. Sometimes friction is considered as an unwanted effect of the design. Dry friction resists relative motion of two solid surfaces in contact. The two types of dry friction are “static friction” between nonmoving surfaces and “kinetic friction” (sliding or dynamic friction) between moving surfaces. In applications such as turbo machinery bladed disks and rotating seals, where structural damping is negligible, dry –friction damping has been widely used to reduce the resonant response of the blades so as to limit the occurrence of wear and premature failure. Having dry friction in the system complicates the dynamic analysis of the system due to its nonlinear nature. Two type of friction damper modeling, namely, macro-slip model and micro slip model are used for such studies.  Macro slip model assumes the entire friction surface as either slipping or stuck. It is an extensively used method due to its mathematical simplicity.  In more realistic micro-slip model, the entire friction surface is modeled as an elastic body, allowing local slipping in the friction element without gross slip. This allows obtaining damping even in the absence of gross slip The early research in this area includes the study by E J Berger (2002) who explained about friction modeling of dynamic system. He concluded that the system model and friction model are fundamentally coupled, and they cannot be chosen independently. Later W. Chen and X. Deng (2005) explained about structural damping caused by micro slip along frictional interfaces at bolted joint. In addition to above George Jureaj Stein and Raduz Zahoransky et al. (2007) proposed a method for analysis and simulation of a general single degree freedom oscillatory system with idealized linear viscous damper and dry friction. In same year E. Chatelet and G. Michon, et al. (2007) proposed a method for choosing the most appropriate contact model from several models, by comparing their efficiency for predicting hysteretic behavior in different applications. Later Christian M. Firrone (2008) has done study performed on the forced response of a mock up system which simulates the flexural behavior of two turbine blades with an interposed under platform damper. In addition to above Daniel J. Dickrell III and W. G. Sawyer (2010) proposed a method to calculate lateral contact stiffness of an elastic foundation. More recently K. Asadi and H. Ahmadian et al. (2012) proposed a procedure to determine stick–slip transition under single-harmonic excitations is derived. The analytical model is verified using experimental vibration test responses performed on a free-frictionally supported beam under lateral loading. In this paper a model is developed and static analysis is carried out to obtain stresses and response of rotating seal. In addition to analysis of seal damper model shear stiffness of friction damper is calculated. Modeling of Rotating Seal and Damper  UnigraphicsNX7.5 is an advanced high- end CAD/CAM/CAE software package developed by Siemens PLM Software, used to build the geometric model of seal damper  ANSYS13 is an engineering simulation software (computer-aided engineering, or CAE) developer. ANSYS offers engineering simulation solution sets in engineering simulation that a design process requires, used to create FE model and solve static and modal analysis Procedure for modeling of seal and damper  First create the 2D sketch of seal damper using unigraphicsNX7.5 as shown in figure 1.  Create .iges file and export it in ANSYS13 and create area using lines.  Mesh 2D model of seal damper using PLANE25 and COMBIN14 element type.  PLANE25 is an Axisymmetric –Harmonic 4-node structural solid Element. The element is defined by four nodes having three degree of freedom per node.  COMBIN14 element has longitudinal or torsional capability in 1D, 2D, and 3D applications. The longitudinal spring damper option is a uniaxial tension-compression element with up to three degree of freedom at each node.