Equal Life Design For Key Parts Of Mining Dump Truck Based On The Stiffness Chain

In this paper, the object of study is a large-tonnage mining truck, relying on the National 863 Program "the large-tonnage dump truck development". Mining dump Truck is the main force of transport in the large open-air ore field. In order to promote the development of independent products, the mining equipment is included in the16 th national congress of major technical equipment in key areas by the state council.Therefore, the use of advanced technology research to develop mining dump truck, is in line with national policy requirements and has important engineering value.Traditional design is mainly aimed at improving product life, usually pursuing the life durability. However, the simple pursuit of life-long structure would tend to bring the quality of redundancy. Thus it will not only cause a huge waste of manufacturing resources, but also increase the difficulty of scrapping. Equal life design idea thinks that life deficiency and redundancy are a kind of waste of resources,and only the limited lifespan and matched functional design, is the most valuable design. There is a phenomenon that the key parts life of mining dump truck are unequal. Frame and A-shaped frame are the main carrying members of mining dump truck, withstanding a strong impact from the road surface. Once breaking, the normal operation of the vehicle will be severely affected, causing millions of casualties or major damage. So it is critical to assure part fatigue life during its operation. However,because the deck member force is small, traditional life design often causes life redundancy, leading the waste of material resources and costs. How to make the parts fatigue life of a reasonable match, can both guarantee life requirements and save manufacturing cost of parts.Reasonable distribution of part stiffness is a way to improve the fatigue life and reduce the mass redundancy. The reasonable stiffness distribution is a resource and performance optimization process. On the one hand, unreasonable stiffness distribution between the components can cause resonance between parts, influencing fatigue life and working conditions. On the other hand, For a individual component,unreasonable stiffness distribution will not only lead to redundant structure, resulting in waste material, but also make a part of the structure is relatively weak member,resulting in fatigue failure in the role of alternating load. Reasonable parts stiffness distribution is the key to ensure good quality of the structure performance and reduce the redundancy. However, the stiffness chain design method is the effective means torealize reasonable distribution of stiffness. Establish an effective stiffness chain design method to associate with the fatigue life and lightweight. Meanwhile, putting stiffness chain design method into equal life optimization design, to achieve a reasonable distribution of stiffness, is an effective way to guarantee fatigue life requirements and lightweight requirements of the parts.For the special structure and working conditions of one domestic mining dump truck, this paper combines experimental work and numerical simulation technology with grey model and stiffness chain to research equal life design of the parts of a mining dump truck. This paper mainly focuses on:1. The vehicle dynamics model is established and used to provide the load boundary conditions of the finite element model and the load spectrum information of fatigue life analysis. Then according to the 3d model of mining dump truck, the finite element models including frame, A-type frame and deck are respectively established.The finite element model analysis results are compared with actual vehicle road test results respectively. The results verify the validity of the finite element model of different parts, so as to provide basic models for fatigue analysis and stiffness design.2. In the case of non-equidistant stress grading statistics, non-equidistant grey model is constructed, and the genetic algorithm is used to optimize the values of background value to ensure the accuracy. And, combining the non-equidistant grey model with Miner rule, the grey Miner method is constructed to predict fatigue life to improve the accuracy of fatigue prediction. Then the fatigue life analysis is carried out on the dump truck key parts. Meanwhile, extract stress time history of the danger point, and the stress classification statistics are done. Finally, the grey Miner method is used to predict the fatigue life of frame, A-type frame and deck, and more accurate fatigue life is obtained.3. Due to the dynamic coupling between the parts, it is easy to cause resonance and damage. From the aspects of mode matching to guide the stiffness distribution between the parts can avoid the happening of this kind of situation. This paper analyzes the modal information of key parts, and the research has done for mode matching between the parts. Stiffness coordination relation between the key parts is established, in order to provide strong guidance of the reasonable design for the key parts.4. For individual components, unreasonable stiffness distribution not only leads to structural redundancy and material wasting, but also leads to that a certain part of the structure is relatively weak, and it is easy to cause fatigue damage. This paperestablishes a stiffness chain design method of components. Based on this method,stiffness distribution models of frame, A-type frame and deck are established. Then research on of stiffness uniformity distribution is done, in order to reduce the structural redundancy and improve the structure performance. This research can provide reasonable stiffness constraints for equal life design.5. The mathematical relationships between the fatigue life and the variables are established using RSM. Reasonable stiffness distribution of the parts as constraint conditions, aiming at fatigue life and mass, equal life optimization model is established under the precondition that equal life design idea is introduced into the key parts design. Then the model is solved by using the genetic algorithm, and equal life design of key parts is realized.