Vibration and noise reduction analysis device and analysis method for panel part of automobile

A vibration and noise reduction analysis device for a panel part of an automobile, the vibration and noise reduction analysis device being configured to reduce vibration and noise of the panel part caused by vibration from a vibration source and a noise source in the automobile and identify a portion at which a weight of an automotive body of the automobile can be reduced, the device comprising:

• a memory storing instructions;
• and
• a processor program med to execute the instructions to:
• acquire an automotive body model including a body frame part model and a panel part model obtained by modeling each of a body frame part and a panel part forming the automotive body of the automobile with a mesh, in which an excitation position where the vibration from the vibration source and the noise source is input is set;
• a plurality of sectioned regions sectioned based on the body frame part model and the panel part model in the automotive body model;
• set, as a vibration and noise reduction target panel part model, a panel part model of a panel part to be reduced in vibration and noise among the panel part models in the automotive body model in response to an instruction from an operator;
• perform vibration analysis using the automotive body model, to obtain a vibration behavior of the vibration and noise reduction target panel part model and a frequency characteristic of equivalent radiation power which is an index of the vibration and noise, and select a vibration mode having a large contribution to the vibration and noise and a peak frequency of the equivalent radiation power corresponding to the vibration mode;
• change a weight of one or a plurality of sectioned regions in the automotive body model, to perform the vibration analysis for each combination of weights of the sectioned regions in the automotive body model, and acquire a peak frequency of equivalent radiation power of the vibration and noise reduction target panel part model in the selected vibration mode;
• perform multivariate analysis in which the peak frequency of the equivalent radiation power of the vibration and noise reduction target panel part model is set as an objective variable and the weight of the sectioned region is set as an explanatory variable, and calculate a contribution degree of the weight of the sectioned region to the peak frequency of the equivalent radiation power of the vibration and noise reduction target panel part model;
• identify a portion to be reduced in weight in the automotive body of the automobile in order to reduce the vibration and noise of the panel part to be reduced in vibration and noise based on the calculated contribution degree of each of the sectioned regions,
• derive a relational expression b tween the peak frequency of the equivalent radiation power of the vibration and noise reduction target panel part model and the weight of each of the sectioned regions;
• select one sectioned region for which a sheet thickness is to be calculated;
• calculate the weight of the selected one sectioned region by giving, to the derived relational expression, a weight of another sectioned region excluding the one sectioned region and the peak frequency of the equivalent radiation power of the vibration and noise reduction target panel part model;
• and
• calculate the sheet thickness of the body frame part model and/or the panel part model forming the one sectioned region based on the calculated weight of the one sectioned region.