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Research on Dynamic Stress Analysis of Marine Diesel Engine Frame

Author: GaoWeiJuan
Tutor: XiangYang
School: Wuhan University of Technology
Course: Marine Engineering
Keywords: Diesel Engine Block Dynamic stress Finite Element Analysis
CLC: U664.121
Type: Master's thesis
Year: 2010
Downloads: 145
Quote: 5
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Abstract

Diesel engine body is the whole skeleton and the basis of the diesel engine, under complex loads in the operation of the diesel engine, the size of these loads, changing direction with the working conditions and the crank angle, some of the point of force is also changing. The body's reliability have an important impact on the entire diesel engine performance, it essentially determines the entire service life of the diesel engine, simple static stress analysis of the body has been unable to meet the demand of this stage diesel engine design, dynamic stress on the body's The analysis is particularly important. Stress analysis method 6L16/24 type diesel engine body dynamic studies, both from the theoretical calculations and experimental test. The main work and conclusions are as follows: 1) under the premise of the calculation accuracy and calculation speed, reasonable simplified solid model 6L16/24 diesel engine block, and establish a finite element model of the dynamic stress. 2) the use of multi-body dynamics analysis software ADAMS computed suffered piston side thrust and stall owners bearing the vertical component and the horizontal component, the loaded dynamic load as the body. 3) finite element model 6L16/24 diesel engine block loaded load, defined displacement boundary conditions, calculation of the dynamic stress in the rotational speed of 1000 rpm, single-cylinder power 90kW conditions running a cycle. 4) analysis of the dynamic stress calculation results, the main draw the following conclusions: the high stress area from the the stress cloud point of view, the diesel engine body is mainly distributed in the upper and lower contact surfaces of the cylinder liner and the body, as well as around the main bearing and subject to dynamic loads greater impact; in near each cylinder angry moment, the thin wall between the upper and lower contact surfaces of the cylinder sleeve and the body of this cylinder, cylinder liners and camshafts as well as the two tranches of around the main bearing stress reaches the maximum value; easy to install cover at the corner areas in the body stress concentration; near the diesel engine flywheel stress value is more stable, basically around a fixed value fluctuations; diesel engine front-end cabinet less stress, only in relatively significant stress and body connection. 5) only consider the case of bolt preload, respectively, using the bolt preload temperature method and the direct method is applied to the body, from the static stress cloud can be seen that the the two loading obtained results consistent, in the body and bearing The seat side connection of stress, and closer to the intermediate file bearing the greater the stress, other regions of the body's stress less obvious. 6) test test and calculation results contrast through trials testing the dynamic strain the 6L16/24 diesel engine block and cylinder pressure test, and the test results with the calculated results were compared to verify the correctness of the finite element method. This innovation are mainly the following: 1) for the loading of the piston side thrust, its action position to consider for the cylinder liner and the body to be assembled upper and lower contact ring surface, respectively the surface of the two parts create a rigid region, with to the coupling surfaces of all nodes to the center point, the piston side thrust loads at that point. 2) for the gas forces on the role of the diesel engine body, the main consideration when the gas force is applied to the cylinder head lower surface, cylinder sleeve in contact with both the surface on the body produced by the biasing force caused by the reaction force of the cylinder head bolt. Analog stiffness test using the finite element method, and the coefficient of relative stiffness of the bolted connection load curve to calculate the cylinder head bolts dynamic role in the cylinder liner in contact with the body surface is uniform. 3) using a variety of computational analysis software is a combination of methods, give full play to the advantages of software: the first processing section, HyperMesh software powerful pre-processing function, convenient and accurate completion of the dynamic stress analysis of pre-treatment; dynamic load of the body calculated using a multi-body dynamics analysis software ADAMS, draw the load magnitude more accurate than the classic calculation method; calculated using RADIOSS solver, body dynamics analysis.

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CLC: > Transportation > Waterway transport > Marine Engineering > Ship machinery > Ship power plant > Internal combustion engine power plant > Diesel engine
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