| There are porous cavity parts with complex shape in automobile engine, pump body, valve and other mechanical structure. In order to meet the cleanliness of the product and ensure product quality. It is important to washing oil, metal shavings and other impurities of porous cavity parts. With the higher requirements of washing quality and the production efficiency of the porous cavity parts. Locating and clamping of the washing fixture are analyzed. There are limitations of washing fixture for porous cavity parts in general, efficient modular, and high precision, economic and other aspects. The nozzle and fixture body model is built. The static characteristic of nozzle is obtained by static analysis. The dynamic characteristics analysis of fixture body is obtained from modal analysis by using the ANSYS.Firstly, the basic method of the fixture structure optimal method and the finite element optimal analysis are proposed in detail. According to locating and clamping principle of fixture, locating and clamping structure of washing fixture is analyzed. Comparing the mechanical clamping structure of the fixture, the clamping structure with rapid clamping mechanism can be proposed. Taking the reliability principle of parts as the goal to establish a mathematical model of the optimization of clamping points, which solved by using the linear weighted method, and the improved scheme of the clamping structure is established. The results show that the clamping scheme can satisfy the stability of parts and improve the clamping rate.Secondly, the nozzle structure model is built by ANSYS. The static characteristics of the nozzle show that the stress distribution on the inner wall of the nozzle is not uniform and there is a stress concentration point. According to energy conversion principle, the energy conservation equation is established to analyze parameter of the nozzle structure. This is diameter and length diameter contraction ratio, angle, contract angle and diffusion angle of the nozzle, which have greater influence on the distribution of pressure on the inner wall of the nozzle. So structures of four kinds of nozzle are proposed. In addition, by comparison the stress distribution, the results show that the conical nozzle D is better than cylindrical nozzle structure. It not only changes location of the stress concentration point, but improves the stress distribution on the inner wall. In order to obtain the optimal structure of conical nozzle, the nozzle diameter and the ratio of length to diameter are optimized.Thirdly, the first ten natural frequencies and corresponding modes of the fixture body are obtained from modal analysis. The results provide important basis for dynamic optimization. According to the result of dynamic response analysis for fixture body, the peak response frequency of fixture body is obtained. The results show the external excitation frequency is close to the natural frequency of the fixture body. Resonance will be happened. So it is necessary to carry on the dynamic optimization for fixture body.Finally, the research based on nozzle structure static analysis is to optimal structure parameters. The results show nozzle diameter has the biggest influence on the pressure on the inner wall of the nozzle by using orthogonal design method. The mass and natural frequency of fixture body is set as the optimization goal. The allowable stress of structure is set as state variable. The diameter of the hole and the height of fixture body are set as design variables. So the structure of fixture body is optimized by ANSYS. The nature frequency of the improved fixture body skips the external excitation frequency. The first mode frequency of the peak response is reduced from 47.369Hz to 43Hz. The resonance phenomenon is weakened, and mass of the fixture body is reduced by 13.3%. The results show that the optimal structure can reduce weight of the structure, and enhance reliability of structure. |
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