5 research outputs found

    Simulation of fluid-structure interaction and impact force on a reed valve

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    The cyclic impact force between a reed valve and the seat plate is the main reason of the valve failure in many thermo-technical devices as compressors, engines, etc. According to experimental observations the latter is due to fatigue and usually occurs in the leading part of the valve ‘neck’. In this work, a complex numerical analysis is presented aimed to studying the external forces and internal stresses suffered by the valve. In particular, the impact force between the valve and the seat is studied. The numerical analysis relies on the coupled synergy of two different simulation concepts. In order to do so, two codes are used: (1) first, the in-house Computational Fluid Dynamics (CFD) code presented in [1] is employed to simulate the Fluid-Structure Interaction (FSI) between gas and valve, extracting reference data for valve displacement and external gas pressures; (2) second, the analysis of the internal structure stresses, together with the impact forces with the plate is implemented in a Computational Solid Dynamics (CSD) code developed in FreeFEM++ [2]. The impact force representation is based on the formulation presented in [3] where a conserving algorithm for frictionless dynamic contact/impact is developed. Due to the importance of obtaining an adequate impact force, an exhaustive study is carried out on its characterization in terms of numerical parameters, such as the penalty stiffness. Under this framework, the valve displacement and impact velocities are verified. Hence, impact forces are analysed in different scenarios, obtaining interesting observations about stresses distribution, with a particular focus on the points where failure is experienced.The authors acknowledge Voestalpine Precision Strip AB company for the previous research collaboration project that allowed to validate experimentally the presented numerical methods. P. Castrillo gratefully acknowledges the Universitat Politecnica de Catalunya and Banco Santander for the financial ` support of his predoctoral grant FPI-UPC (109 FPI-UPC 2018). E. Schillaci acknowledges the financial support of the Programa Torres Quevedo (PTQ2018-010060). This work has also been financially supported by a competitive R+D project (ENE2017-88697-R) by the Spanish Research Agency.Postprint (published version

    High-order cell-centered finite volume method for solid dynamics on unstructured meshes

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    This paper introduces a high-order finite volume method for solving solid dynamics problems on three-dimensional unstructured meshes. The method is based on truncated Taylor series constructed about each control volume face using the least squares method, extending the classical finite volume method to arbitrary interpolation orders. As verification tests, a static analytical example for small deformations, a hyperelastic cantilever beam with large deformations, and a cantilever beam subject to a dynamic load are analyzed. The results provide an optimal set of parameters for the interpolation method and allow a comparison with other classic schemes, yielding to improved results in terms of accuracy and computational cost. The final test consists in the simulation of a compressor reed valve in a dynamic scenario mimicking real-life conditions. Numerical results are compared against experimental data in terms of displacements and velocity; then, a comprehensive physical analysis of stresses, caused by bending and impact of the valve, is carried out. Overall, the method is demonstrated to be accurate and effective in handling shear locking, stress concentrations, and complex geometries and improves the effectiveness of the finite volume method for solving structural problems.The authors acknowledge Voestalpine Precision Strip AB company for the previous research collaboration project that allows to experimentally validate the numerical method presented. P. Castrillo gratefully acknowledges the Universitat Politècnica de Catalunya and Banco Santander for the financial support of his predoctoral grant FPI-UPC (109 FPI-UPC 2018). E. Schillaci acknowledges the financial support of the Programa Torres Quevedo (PTQ2018-010060). The authors would like to thank Professor Alfredo Canelas for his support during the development of the current work.Peer ReviewedPostprint (author's final draft

    High-order finite volume method for linear elasticity on unstructured meshes

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    This paper presents a high-order finite volume method for solving linear elasticity problems on two-dimensional unstructured meshes. The method is designed to increase the effectiveness of finite volume methods in solving structural problems affected by shear locking. The particular feature of the proposed method is the use of Moving Least Squares (MLS) and Local Regression Estimators (LRE). Unlike other approaches proposed before, these interpolation schemes lead to a natural and simple extension of the classical finite volume method to arbitrary order. The unknowns of the problem are still the nodal values of the displacement which are obtained implicitly in a direct solution strategy. Some canonical tests are performed to demonstrate the accuracy of the method. An analytical example is considered to evaluate the sensitivity of the solution concerning the parameters of the algorithm. A thin curved beam and a crack problem are considered to show that the method can deal with the shear locking effect, stress concentrations, and geometries where unstructured meshes are required. An overall better behavior of the LRE is observed. A comparison between low and high-order schemes is presented, and a set of parameters for the interpolation method is found, delivering good results for the proposed cases.P. Castrillo gratefully acknowledges the Universitat Politècnica de Catalunya and Banco Santander for the financial support of his predoctoral grant FPI-UPC (109 FPI-UPC 2018). A. Canelas thanks the Uruguayan research councils ANII and CSIC for the financial support.Peer ReviewedPostprint (author's final draft
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