Stress singularity arises in MEMS devices due to sudden geometric and material variation. Sharp notches are common example of sudden geometric variation, which often occurs during the fabrication process of MEMS components. The magnitude of the stress field induced due to stress singularity is given by the value of the notch stress intensity, K. The stress intensity is depended on the notch geometry and the type of loading (mode Ⅰ, mode Ⅱ and mode Ⅲ). Fracture failure at the notch occurs when notch stress intensity reach fracture toughness, K_C. An electrostatically actuated test device used for the analysis of a notched micro beam specimen under three-point loading will be presented. The objective of this study was to investigate the effect of geometric configuration on the stress field around singularity for a micro beam specimen by asymptotic, numerical and probabilistic analysis. The scope of work is fourfold. First, the effect of notch angle on the strength of the singularity is determined using two different asymptotic analysis methods - complex potential method and Airy stress function method. Second, the effect of the angular variation (for different notch angle) on the influence coefficients is determined using analytical methods. Third, the effect of the notch angle and depth on the stress intensity factor is determined using finite element methods and contour integral method. Fourth, the probabilistic analysis of maximum stress developed in the micro beam specimen is performed.
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