چكيده به لاتين
Abstract
A frame is counted as the most important part of a bicycle and it’s subjected to different static and dynamic loads onto which wheels and other required components are attached. The modern and most common frame design for an upright bicycle is based on the safety bicycle, and consists of two triangles, a main triangle and a paired rear triangle. This is known as the diamond frame. Frames are required to be strong, stiff and light, which they do by combining different materials and shapes. Performance of a bicycle is closely dependent on its weight, so, a well-designed frame can be the best solution to optimize the overall performance. This work has outlinedS a CAD model which represents a mountain bicycle frame utilizing Parabolic OCTREE Tetrahedron Mesh for a proper analysis. The objective was to optimize weight and vertical stiffness by means of FEA software and to manufacture the optimized model to validate the whole evaluation afterwards. The frame was modeled using CAD software; it was then validated by a special test. The testing system contained subject frames (before and after optimization), a computerized hydraulic press-brake with load cell and extension sensor and a set of specialized fixtures. With comparing quasi-static load simulation and the experiment, it was confirmed that the simulation is valid. With extracting required drafts from optimized model, a new bicycle frame was manufactured and tested. Comparing final simulation and experiment, results indicates 12% decrease in frame weight and 8% increase in its vertical stiffness.
Keywords: bicycle, frame, optimization, CAD, FEA, weight, extension.
