Compilation method of power train load spectrum of engineering vehicle

To study the compilation method for load spectrum of engineering vehicle power transmission, the load signals of a wheel loader were collected in 5 typical cases. The operating cycle was divided into six operating sections for signal processing. The real load signals that reflect dynamic variation of torque loads, were obtained after signals pretreatment and characteristics analysis. The load signals of the rear drive flange were taken as an illustration. The measured load time histories were processed by means of rain flow counting method. After statistical analysis, it was found that the distributions of load amplitude and mean were independent and obeyed Weibull distribution with three-parameter and normal distribution respectively in shoveling section. The mean of the normal distribution was 1910 N·m, and the standard deviation was 537.8 N·m. According to the time proportion of typical cases, frequencies were extrapolated and synthesized. Two-dimensional load spectrum with 8×8 levels was established with joint probability distribution function. After two-dimensional load spectra were transformed into one-dimensional 8-level load spectra with Goodman method, the program loading spectrum of power transmission, which represent the factual load conditions, was compiled. This study can provide a foundation for accurate fatigue life prediction and fatigue test.