Papers by Author: Yan Song Wang

Abstract: Sheet metal parts are widely used in auto body and airplane body. As the method of influence coefficient cannot accurately analyze the relationship between part deviations and assembly variations, this paper proposes a new variation analysis model based on a method of power balance for sheet metal parts. The simple metal planes are loaded to fixtures according to the principle of “4-2-1”; and then variety of part deviations is analyzed during assembly process. The analysis shows that the welding guns do same work during welding process. Based on the above, this work establishes sensitive coefficient matrices between part deviations and assembly variations. Finally, two Z-shape sheet metal parts illustrate the assembling variation analysis process and the results indicate the accuracy of the method of power balance.

Abstract: Sound insulation equation of steel panel and other insulation materials of compound panel was deduced in normal case, based on the Wave Transferring theory in this paper. Single steel panel and compound steel panel with a certain thickness were predicted theoretically and then measured in the standing wave tube practically. Compared with the two results, the predicted values were matched with the measured values.

Abstract: Based on a hybrid transfer-matrix method, a new standing wave-duct system with four microphones for acoustical property prediction of multi-layered noise control materials is developed in this paper. In this system, the two-load method (TLM) and two-cavity method (TCM) are used for computing the transfer matrix of each material sample. The transfer matrices saved in a database in the system hardisk may be selected for predicting both the absorption ratio and transmission loss of a multi-layered treatment of materials. Verification results suggest that the newly designed standing wave-duct system is effective for acoustical prediction of multilayer material configurations.

Abstract: This paper proposes a genetic algorithm to generate and optimize assembly sequences for compliant assemblies. An assembly modeling is presented to describe the geometry of the assembly, which includes three sets of parts, relationships and joints among the parts. Based on the assembly modeling, an assembly sequence is denoted as an individual, which is assigned an evaluation function that consists of the fitness and constraint functions. The fitness function is used to evaluate feasible sequences; in addition, the constraint function is employed to evolve unfeasible sequences. The genetic algorithm starts with a randomly initial population of chromosomes, evolves new populations by using reproduction, crossover and mutation operations, and terminates until acceptable sequences output. Finally an auto-body side assembly is used to illustrate the algorithm of assembly sequence generation and optimization.

Abstract: A standing wave-tube system for acoustical property measurement of vehicle-used sound absorption materials is developed in this paper. Theoretically, the standing wave ratio method and the two-cavity method with two-microphone configurations are combined and applied for calculating some acoustical parameters, such as sound absorption ratio, reflection coefficient, characteristic impedance, propagation constant, of a sample material. Based on the combined method, the standing wave-tube system including two microphones, an A/D board, a signal amplifier, a DSP computer and a set of software is carefully designed and performed. The verification results suggest that the newly designed system is accurate for acoustical property measurement of the materials used on vehicles. It can be directly used for selecting noise-control materials in vehicle acoustical designs.

Abstract: Based on the measured and denoised vehicle engine noises, the sound quality evaluation (SQE) techniques in common use for A-weighting sound pressure level (SPL) and psychoacoustical parameters, such as loudness, sharpness and roughness, are performed and compared in this paper. The wavelet threshold shrinkage method is adopted for sound signal denoising. The comparisons suggest that the A-weighting SPL is not sufficient and can only be used as a reference in vehicle SQE, the psychoacoustical parameters can provide a complete description and more exactly reflect to the subjective feeling of vehicle noises, should be considered in vehicle designs.