A STUDY OF MECHANICAL ROBUSTNESS OF PORTABLE ELECTRONIC DEVICE SUBJECTED TO MECHANICAL DROP

• Main Author: TAN , YINN HOONG
• Format: Final Year Project
• Language: English
• Published: Universiti Teknologi PETRONAS 2008
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://utpedia.utp.edu.my/9735/1/2008%20-%20A%20Study%20of%20Mechanical%20Robustness%20of%20Portable%20Electronic%20Device%20Subjected%20to%20Mechanical%20Dro.pdf; http://utpedia.utp.edu.my/9735/

Mechanical drop is one of the main factors which cause damage to electronic devices especially to mobile phone. The effect of mechanical drop has caused electronic and material failure to mobile phones. The objectives of this project are to conduct simulation and physical drop tests in order to analyze the mechanical drop effects on the mobile phone. The constraints are the physical drop tests are high cost and the results can only be analyzed by visual inspection. The cost constraint has caused a limitation to only two drop test specimens which are two function-able mobile phones model Nokia 3310. The methodology of this project is to set up a drop test plan based on the ASTM Standard (D 5276-98), followed by conducting physical and simulation drop testing. One drop specimen is used for each type of drop: Flat Drop and Edge Drop. Both drops are static free fall from a height of l.Om onto a concrete impact surface. Additional multiple dummy drops are conducted by using a dummy phone to obtain a more consistent drop procedure. This is because the drop specimens are allowed to be dropped once to prevent cumulative drop impact damage from affecting the results. The physical drop tests are recorded using a video camera and the video is split into multiple images using software. The physical drop tests show that edge drop sustains higher impact energy which causes material failure. As for simulation drop test, a solid model of the mobile phone is done using 3D Laser Digitizer and CATIA but the modeling file could not be open in ANSYS. Instead, a PDA ANSYS model is used as a replacement for the mobile phone model. The PDA model is then assigned elements and materials properties for the simulation drop test using the ANSYS LS-DYNA Drop Test Module (DTM). There were several problems occurred during the simulation which prevents it from completing. As a conclusion, all the objectives set are met except for the simulation drop test which is still under troubleshooting.