According to the use condition of dump truck unloading goods, the articulated equipment of cargo body and secondary frame take all the lifting weight, which causes that secondary frame carries the concentrated load. Besides, the dump truck loads goods with large construction machinery, so the phenomenon of biased loading goods frequently happens. And in unloading process, because the biased load of goods will make the stress of secondary frame worse, in the process of force analysis of unloading, it’s enough to analyze the strength of secondary frame only. This paper, basing on ANSYS, makes an analysis on the force of secondary frame in the dump truck unloading condition, and the analysis results indicate that the position of larger stress concentration of secondary frame lies in the second half part of secondary frame in the unloading condition, thereinto, the position of Maximum lies in the back flip axis of secondary frame, while the second Maximum lies nearby the position where the balance frame beam is installed on the auxiliary beam. As the result, this paper suggests that the structure of these places of secondary frame should be strengthened in structural design.

The force on dump truck body is telatively complicated, and different unloading working conditions will have effects on the body structure of dump truck. This paper made a modal analysis and feature buckling analysis of the body structure of dump truck under the unloading situation, and also made a nonlinear analysis under the certain circumstances. Through the ANSYS analysis, the body vibration frequency and buckling modal shape was calculated and figured out, and the design of dump truck body was optimized in order to make sure that the stiffness and stability meet the needs.

As the global shortage of oil resources and the rapid increase in car ownership, using gas as the alternative fuel is getting more and more important. Gas fuel, such as CNG (compressed natural gas)/LNG (liquefied natural gas) and LPG (liquefied petroleum gas), with resource-rich, less pollution and other features, are desirable alternative fuels for cars. Through engine bench test, a comparative analysis of power performance between LPG-single fuel engine and gasoline engine was done. The result shows that, by applying LPG injection on single-fuel engine, the power of the LPG engine increases to a higher level than gasoline engines. And combined with the analysis based on the study of domestic development of NGV, predictions could be made that new fuel vehicles will be well utilized in future.