The Structural Strength And Modal Analysis On 300T Fixed Type Full Circle Swinging Crane

With the development of technology and industry,the requirement of the lightweight of mechanical structure is increasing. Manufacturing industry of our country is facing the huge challenge, especially in the crane industry. The crane carries on hoisting, transportation, loading and unloading or the installment to the materials. It has a rather wide application in the various branches and sectors of national economy, and it is important in modern manufacture industry. The crane has the important influences to enhance productivity, guarantee the product quality, reduce the labor intensity and the production cost, enhance the transportation efficiency, speed up the turnover and circulation of goods and materials. The crane is essential auxiliary facility in the process of modernization production. It's also the essential production equipment to organize production reasonably. It has remarkable function on safety production and reducing the accidents. In order to win the domestic and foreign markets, we should enhance the production technology of the cranes, study and improve the crane's structure. This can make it reasonable, convenient and economical, and have an important practical significance.The static strength has been regarded as the main design standard in crane design for many years. With the development of nowadays industry and technique, the hoisting and conveying machinery become more and more large, the load and running speed of machine also become higher and higher, which result in greater dynamic load of machine vibration. With the use of classic mechanics, there are too many hypotheses and predilection in the calculation of complex structures, so the veracity of results is not very good. Dynamic design is an active and positive method which takes librates restraining into account during the course of design. Usually, structure design is a course finished step-by-step, which divided into such 3 phases as primary design, details design and validate design. In recent years, with the development of computer science, it is an inevitable tendency for the design of port crane to develop from the static design to the dynamic design. Dynamic design technique is an important part of modern design method. Technique of finite element method is the important base of theory and powerful tool in mechanical dynamic design.Tower crane is the vital equipment for lifting materials in the working sites. The working reliability of the tower crane is the guideline of ensuring the safety of all the condition. But nowadays, there are more and higher or plate type construction needed to be built, so tower crane are very busy to lift goods. The static stress in the steel structure of tower crane is higher than before. In this dissertation,the basic idea,mechanical foundation of finite-element method and the theory of buckling stability analysis are expatiated in detail. The function and open style structure of the finite-element analysis software ALGOR,and the main features of ALGOR are concretely explained. This study mainly concentrated in the overall structure of the intensity and modal analysis with fixed slewing crane. The paper based on analysis of fixed-slewing crane as the research object, the establishment of a crane used ALGOR simulation model, the comprehensive analysis of various cranes work load, we determine four typical operating modes through each kind of load, then we carry on the strength analysis, and have all the cranes in the status of the stress distribution and displacement. The results show that the maximum stress in the structure of the situation in the second part of drawbars, stress value is 251.655 MPa, in order to guarantee the strength of the structure, the increase should be in the region of the cross-section bar area. Most of the crane structural strength to meet the stress requirements, only a few parts which are bigger than 200MPa the stress mainly to concentrate in the arm head's angle-ear part and turnplate's angle-ear part, this is inevitable in the model simplification process, Because of the simplified process, we usually use the divergence of Pin-to replace part of this will have and does not conform to the actual results, but it does not affect the structural strength that these stress we usually think it is neglected .From the modal analysis, as fixed-full-circle rotation symmetric structure of the crane, some numerical vibration frequency is very similar to that when the external excitation frequency close to the natural frequency, may have a greater amplitude, so that structural damage, can modify the design to change the complete machine vibration frequency range to enhance the operator's comfort.By ALGOR software emulating it may save manpower and material resources and have relatively simulation precision. It is very helpful to advance the crane structure dynamics design level in engineering. It makes the crane structure more reasonable and meets demand of social development. Through this study,we can find the function and significance of ALGOR is showed in strength analysis and optimum design. The study method of this paper is fit to the analysis of other kinds machinery.