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RISS 인기검색어
- 검색키워드
- 저자 : Haojie Xu (검색결과 2 건)
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Design and analysis of fiber placement for composite conical shell
Haojie Xu,Jiuru Lu,Kangmei Li,Jun Hu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.3
Composite conical shells have a wide range of applications. The 3D printing technology based on FDM constrains the fibers in a plane and it is difficult to fill the fibers in the thin wall. This paper proposes a rapid prototyping method for composite materials based on curved surface fiber placement. The conical shell is divided into a series of equidistant offset surfaces. Then we designed three initial paths for fiber placement and rotated them to cover the surface of the conical shell. The resin paths are designed for filling the border layers and the gaps between the fibers. The placement process is simulated by MATLAB (R2016b) and we analyzed the parameter range, direction angle, curvature and fiber content of the three paths. When the critical parameters 0 ϕ = [0°, 42°], ξ is equal to any value and C = (0, 0.032], the corresponding initial path can reach the top of the cone shell in this study. The direction of the constant curvature curve can be designed best; when C = 0.032, the direction angle range is -90 to 90. The curvature of the geodesic path is the smallest; when 0 ϕ = 10°, the normal curvature is about 0.0001 and the geodesic curvature is equal to 0. The fiber content of the geodesic path is greatly affected by the parameter 0 ϕ , and the difference can reach 40 %. The fiber content of the linear curve is greater than 90 %. When ξ is equal to 4, the fiber content is 95 %. For the constant curvature curve, the fiber content is generally very low, about 20 %. We used a six-axis robot and a spindle to produce composite conical shell. The results show that the present design method for composite conical shell is reliable and is able to provide a useful reference for design and production of composite conical shell.
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INFLUENCE OF INLET WATER INJECTION ON ENERGY CONSERVATION AND EMISSION OF GASOLINE ENGINE
Xu Jiangtao,Zhou Zhiyuan,Jiang Liyi,Zhou Haojie,Zhang Chuan 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.4
Increased compression ratio of auto engine can effectively improve thermal efficiency. However, the risk of engine knock becomes higher when increasing the intake boosting. In this paper, the role of an inlet Water Injection (WI) system in improving the performance of a spark ignition engine was investigated, which was through a comparative study of Miller cycle with electromagnetic intake valve train (EMIT). The numerical simulation method was developed in AVL BOOST based on the engine test rig, and then the port water injection modelling was introduced. The results showed that when the engine speed was lower than 1800 r/min, the water spray scheme had a better effect on the engine performance as compared with the Miller cycle, and such advantage was increasingly significant with the decrease of the speed. This is due to the fact that the water injection takes into account the temperature reduction in the cylinder. When the engine speed was over 1800 r/min, it had a negative impact on engine performance with IWI due to the excessive suppression of combustion. This study provides a theoretical basis for design and research of gasoline engines
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