Industrial Collaboration Project between
National
University of Singapore and
Motorola Electronics (S) Pte Ltd
STUDY OF PHYSICAL ROBUSTNESS OF SMALL ELECTRONICS CONSUMER PRODUCTS
INTRODUCTION
Electronic consumer products like portable CD players, pagers, etc. must exhibit a
certain level of mechanical robustness when subjected to specific impact shock. This is
an essential factor many consumers look at.
This project is part of a collaborative effort between NUS and Motorola Electronics (S) Pte Ltd. The experimental setup involves impacting pagers at different orientations and heights to assess damages in pagers to help in the design process.
Finite element software ABAQUS/Explicit is used to simulate pager impact tests and numerical results obtained are verified with those obtained experimentally.
RESULTS
Fig. 1 - Impact force vs impact duration at different drop heights
Figure 1 shows a sample data set whereby the pager is dropped from different heights impacted at a corner. The corner of impact makes an angle of 45 degrees with the plane of impact while both the front and back face is orthogonal to the plane.
It is noted that the same orientation gives the same impact behaviour(ie. the subsequent motion) even for different drop heights. At higher drop height, the impact force experience is larger due to higher kinetic energy at impact. The impact duration is also shorter.
Fig. 2 - Impact force vs impact duration at the same drop height
The sample data in Fig. 2 shows the impacting force vs impact durations of the pager impacting from 0.6m at different orientations. Different orientaions would yield different impact behaviour. The impact force captured for the pager impacting at an edge is highest because of the lower rotational kinetic energy it carries upon impact.
Therefore impact behaviour is found to be highly dependent on impact orientation while impact velocity(or drop height) determines the magnitude of the impact force and impact duration.
CONCLUSION
In conclusion, the correlations between impact orientation and drop height to parameters
like impact force, impact duration are established. The finite element model created is able to match the general behaviour of the experimental
impacts. Therefore, finite element models can be used to simulation impact mechanics situations.
Thus, the project better integrated the research in experimental testing and computational analysis. This helps to speed up the product design process and also bring about a reduction in costs as well.
Although this project encompasses the impact of pagers, the same approach can definitely be used to investigate the physical robustness of other small electronic products too.
For more information, please contact :
Student : Teo Yep Min
Email : yepmin@post1.com
Supervisor : Dr Lim Chwee Teck
Email : mpelimct@nus.edu.sg
Impact Mechanics Laboratory
Department of Mechanical Engineering
National University of Singapore
10 Kent Ridge Cresent
Singapore 119260
Drop me a email at yepmin@post1.com
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