Research On Fatigue For The Chassis Structure Of Tire Crane

The operation of the tire crane is in intermittent cyclical, often frequently lifting up or loading down, and starting or stopping. Because of its high working speed, as well as relatively complex and heavy working conditions; at the same time, it is loaded by the cycle of alternating load, thus the metal structure prone to fatigue cracking, that is a serious security threat to the normal production. There are a lot of research about fatigue failure of the crane have been made at home and abroad, but most related to the bridge crane using in the port, this type of crane is usually working with out the slewing mechanism. The slewing operations of crane will be more severe operating conditions, the resulting stress increase is even more prone to fatigue failure. There are a few fatigue research related to the portal crane, but portal crane boom due to the use weight balance system, you can turn the whole range of amplitude and operations, and only in accordance with the tire cranes lifting capacity table under a different rate relative to rated capacity. In view of this, it is necessary to do a fatigue analysis about the port tire cranes.Tire crane chassis is an important bearing structure, due to the relatively heavy working conditions and the complex stress state, it is easy to get fatigue damage and cracks. In the previous design of the tire crane, the main experience in the design and static strength in accordance with design methods, usually select the larger the allowable safety factor, or choose to increase the allowable stress of the material are two ways to reduce the structural damage. But this will increase the thickness or the use of high strength steel, but this closely is to improve the static strength of components, there are still structural fatigue failure may occur because of fatigue failure is different from static damage. Fatigue cracks often conceive in the dangerous area of the structure, and then crack propagate until the structural break. Therefore, we must take reasonable ways to reduce the peak stress of the dangerous point, or increase the local area material strength near the dangerous point, in this way to improve its fatigue strength, thereby ensuring the safely and efficient operation of the tire cranes. This thesis introduces the basic concepts of fatigue, fatigue strength theory and all the three finite element analysis software used in this thesis; then using MSC.Patran software to get the structural modeling of the tire crane chassis, rationally analyse the loading conditions and loading methods; and adjust the local place of the model constantly, then use the MSC.Nastran for static analysis, static strength checking stiffness associated; to "crane design specifications" as the standard, the results of a variety of chassis static analysis of working conditions. Follow the steps to the fatigue strength, the fatigue that may point to guide the correction of the design; crane chassis through the typical working conditions are related to the transient analysis of the stress spectrum, combined with the query by S-N curve on the end use of MSC.Fatigue frame structure of the entire life span analysis, to get the cloud life cycle of the chassis structure and make a correlation analysis.