Computer Motherboard Modal Analysis

Computer is one of the most widely used electronic equipment. Motherboard is the core hardware of computer, and its dynamic behaviors have significant effect on the behavior and reliability of the device. In order to ensure and enhance the quality of computer, it is necessary to conduct dynamic analysis on motherboard.To this end, modal analysis on motherboard is performed in the paper, and some issues, including analysis method, test scheme, modeling, means to increase accuracy, optimization, and etc., are addressed. The research work conducted in the paper is outlined as following.1 .Test modal analysis of motherboard. The modal test is carried out by SIMO (Single Input Multiple Output) method, and modal parameters of the motherboard are extracted by multiple reference point modal parameter extraction method in frequency domain. The indeterminable of this test derives from how to determine the excitation signal and place.2. Material parameter test. Preparing for modeling the motherboard, the material parameters of some main parts are measured in this test. Electrical-resistance strain-measurement method is used to determine the elastic modulus and Poison's ration. The problem of stiffening effect of strain gage in measurement is solved by software.3.Finite element modeling. According to finite element (FE) modeling theory, I creates the motherboard's finite element model basing on the work of material test. During the modeling both computing precision and model size are considering, and geometry shape of some parts are handled at convenience of modeling. Some methods and laws for FE modeling are summed in the phase.4.Numerical modal analysis. Lanczos algorithm is used to solve the FE model of motherboard because of its high solver precision and low time-consuming. The dynamic behavior of motherboard is analysis according test and numerical modal parameters synthetically.5. Optimization of FE model. According to the comparison of test and numerical modal parameters, the FE model of motherboard is optimized in three ways, i.e. altering the FE geometry shape, reducing element length of FE model and using higher order elements. Numerical modal parameters are more correlative with those of test after optimization. Optimizing FE model is another indeterminable of the subject.Some methods and laws of how to improve computing precision of FE model are gained in this phase.Creatively, the paper extracts the modal parameters of motherboard by using test modal method and numerical modal method synthetically. It provides references and authorities for improving the dynamic behavior of motherboard. To avoid deficiency of empirical design method in our country, the subject worth while reference for electronic equipment design.