Compilation of Multiaxial Load Spectra for Fatigue Durability of Special Vehicle Based on Extreme Value Extrapolation
The service load spectrum of off-road special vehicle is the key to the structural durability of the vehicle.A method for compiling the multiaxial load spectra for the fatigue durability of special vehicle based on extreme value extrapolation is proposed.Considering the phase relationship between the load channels during the extrapolation of multiaxial load spectra,the equivalent synthesis of multiaxial loads based on the critical plane damage parameter is studied.A multiaxial extrapolation model for the exceedance of extreme value being subjected to the generalized Pareto distribution is extablished.The load spectra are extrapolated using the equivalent synthesized load spectra,and the extrapolated variation is allocated to each load channel based on the synthesis coefficient to achieve the multiaxial load extrapolation considering the phase relationship.The multiaxial extrapolation is conducted by taking the six-directional force signal at the wheel center of special vehicles under typical working conditions as the objective.The aspects of the load spectra before and after extrapolation and the load spectra acquisited are all compared in terms of phase relationship,level crossing counting,rainflow counting and power spectral density.The results indicate that the multiaxial load compilation of special vehicle fatigue durability based on extreme value extrapolation can be used to effectively predict the multiaxial load spectra under the same typical working conditions.
special vehiclemultiaxial load spectraextreme extrapolationphase relationship
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