The three dimensional displacements fields in a surface mounted plastic quad flat pack (PQFP) assembly are measured during power cycling using a combination of holographic interferometry and high sensitivity moire int...The three dimensional displacements fields in a surface mounted plastic quad flat pack (PQFP) assembly are measured during power cycling using a combination of holographic interferometry and high sensitivity moire interferometry. Detailed in plane and out of plane whole field displacement data of the top and bottom ends of the gull wing leads and their distributions along the edge of PQFP are provided. The maximum deformations of the gull wing leads occur at the four corners of the PQFP. The experimental results are used as displacement boundary condition in a linear elastic analysis of the thermal stresses of the corner lead and its solder joint using a 3 D finite element method (FEM). The highest stresses occur in the area connecting the lead and the solder joint. The results should be useful in the evaluation of thermal fatigue damage of surface mount assemblies.展开更多
A simplified mathematical model was created for measurement of thermal expansion coefficients of thinsheet materials with holographic technique. Experimental set-ups corresponding to the mathematicalmodel were designe...A simplified mathematical model was created for measurement of thermal expansion coefficients of thinsheet materials with holographic technique. Experimental set-ups corresponding to the mathematicalmodel were designed and built for both tests above room temperature and at low temperatures. Afringe control technique was introduced for low temperature measurements to compensate rigid bodymovement. Thin sheet specimens of silicon and aluminum alloy (7075) were tested with the developedtechnique. The tested results are in good agreement with reported data and thus verify the validityof the developed technique. The thermal expansion coefficients of the tested materials ranged from2.5×10-6C-1 to 23.6×0-60C-1.展开更多
In this paper, the principle of phase-shift interferometry is first briefly introduced. Then it is used as an illustration to measure small surface deformation, and the measurement accuracy of 0.02μis obtained. This ...In this paper, the principle of phase-shift interferometry is first briefly introduced. Then it is used as an illustration to measure small surface deformation, and the measurement accuracy of 0.02μis obtained. This demonstrates that the technology has great significance for strain analysis in experimental mechanics.展开更多
文摘The three dimensional displacements fields in a surface mounted plastic quad flat pack (PQFP) assembly are measured during power cycling using a combination of holographic interferometry and high sensitivity moire interferometry. Detailed in plane and out of plane whole field displacement data of the top and bottom ends of the gull wing leads and their distributions along the edge of PQFP are provided. The maximum deformations of the gull wing leads occur at the four corners of the PQFP. The experimental results are used as displacement boundary condition in a linear elastic analysis of the thermal stresses of the corner lead and its solder joint using a 3 D finite element method (FEM). The highest stresses occur in the area connecting the lead and the solder joint. The results should be useful in the evaluation of thermal fatigue damage of surface mount assemblies.
文摘A simplified mathematical model was created for measurement of thermal expansion coefficients of thinsheet materials with holographic technique. Experimental set-ups corresponding to the mathematicalmodel were designed and built for both tests above room temperature and at low temperatures. Afringe control technique was introduced for low temperature measurements to compensate rigid bodymovement. Thin sheet specimens of silicon and aluminum alloy (7075) were tested with the developedtechnique. The tested results are in good agreement with reported data and thus verify the validityof the developed technique. The thermal expansion coefficients of the tested materials ranged from2.5×10-6C-1 to 23.6×0-60C-1.
文摘In this paper, the principle of phase-shift interferometry is first briefly introduced. Then it is used as an illustration to measure small surface deformation, and the measurement accuracy of 0.02μis obtained. This demonstrates that the technology has great significance for strain analysis in experimental mechanics.
