Based on the theory of structural dynamics and Workbench software, the modal analysis and harmonic response analysis of a radar vibration fixture are carried out 1 . The results show that the first ...order natural frequency of the fixture is low, and the difference of harmonic response between the sample points is large. By optimizing design and simulation analysis, the new fixture is obtained. The simulation results show that the first order natural frequency of the new fixture is increased by 49.1% and the difference between the sample points is reduced. The radar successfully passed the vibration test by using the new fixture 2 .
In view of the harsh conditions of vibration test of complex integrated circuits in aerospace and the complex characteristics of chip packaging, the vibration fixture optimization design method based ...on topology optimization and multi-objective genetic algorithm is adopted to optimize the fixture structure design for a complex integrated circuit in PGA273 for aerospace. The sweep frequency vibration and random vibration response of the fixture structure are simulated and analyzed. Finally, the validity and rationality of the fixture design was proved by experiments, which effectively solve the problems of test resonance, poor dynamic response and excessive fixture mass.
Board level vibration testing is an important characterization aspect that has to be considered during development and release of electronic components in applications involving harsh environments. ...Industrial reliability test standards prescribed by JEDEC recommend to stress a statistical representative sample size of at least 30 components. Consequently, the test execution time is undesirably long when testing all components sequentially. This paper provides a solution by developing a vibration test approach for simultaneously stressing multiple PCB assemblies. To start with, multiple boards are evaluated via vibrational spectrum analysis that is combined with a Finite Element Model (FEM) to calculate the strain at solder joint level. Limited variation is seen in calculated strain levels from PCB to PCB. This permits simultaneous testing of multiple PCB assemblies. Consequently, three test capacity expansion arrangements, namely One Dimensional (1D), Two Dimensional (2D: Stacked & Side by Side) & Three Dimensional (3D) test methods are evaluated. When comparing the investigated test extension strategies, it is found that test approach with stacked PCB levels alter the stress transferred to the component and can lead to a false reliability prediction. Depending upon the allowed mass load limit of the shaker system and stress levels involved, both 1D and 3D techniques can be used as complementary to one another. Outcomes of this study can further be used to provide guidance for future board level vibration test method.
This paper introduces a kind of vibration fixture which can support products undergo vibration simultaneously along three mutually orthogonal axes on the electromagnetic shaker, and the ratio of the ...vibration values along three product installation directions is coincident with the theoretical set value. Moreover, the vibration feature and design scheme of this multi-axis vibration fixture are discussed. It is found that using this multi-axis vibration fixture on the electromagnetic shaker can avoid the problems currently existing in the vibration testing using the pneumatic hammer shaker and the electromagnetic shaker, such as random vibration frequency spectrum of the pneumatic hammer shaker is uncontrollable and the electromagnetic shaker can only perform uniaxial vibration testing, etc. Finally, the vibration feature of the multi-axis vibration fixture is verified by a testing.
