Nowadays an automotive industry steadily has been growing and playing a major role on economy development for many years. The crash box is one of the most important parts for safety but it was found that the crash boxes manufactured domestically are not met international standard requirements. This is due to process and material limitation. This process for automotive safety test requires high budget and there is unclear approach for specific test. Therefore a study of crash boxes referred to energy absorption project was conducted as an alternative choice of testing. Regarding to the problems as addressed above this project was aimed to design and test crash boxes which come in various structures; simple type corrugated type and honeycomb type of crash box. In addition it was also emphasized in studying energy absorption behavior and physical deformation of crash boxes after dynamic and static energy being applied. Numeric simulation and static test methodology of front collision were applied for these tests in reference to USA NCAP standard for automobile collision test. Testing all types of crash boxes indicated that the corrugated type was able to absorb energy at 2.8% and 5.9% higher than honeycomb type and rectangular type respectively. This is capable to pick up stress and strain continually and effecting to more energy absorb than another type. Additionally this corrugated structure is feasible and suitable for crash box design in automotive manufacturing.

Electronic load is an importance part of power supplies testing system. For non-electronic load type it is required to replace a resister with a new one leading to complicated working procedure. The modern power electronic technology is employ to solve this problem. The electronic load can vary the value following user command. Imported electronic load is costly leading Thailand to have a balance of trade deficit. This article proposes design and implement of an economical cost 30V 1 k DC-Electronic Load controlled by Microcontroller. The tested results can confirm the validity of this proposed electronic load

The objective of this work is to study the effect of the surface roughness on the measured hardness. The preparation of the surface roughness level complied with the ISO 1302: 1992 standard. There are many factors influencing surface roughness such as building mac uncry feed rate speed machine settings cutter and water cooling. The surface roughness C.tU. by these factors will have influence on the measured hardness of materials. The SKS3 is used as material in this study. Surface of the work piece was adjusted with different roughness val es divided following four levels: 12-50 urn rough machined 1.6-6.3 urn smooth turned 0.2-0.8 urn and 0.025-0.1 um. Then all the adjusted roughness work pieces were harden. After the Harden process the hardness of all work pieces were 62-64 HRC. From the measured hardness results it was found that the standard deviations are 4.665 1.0310.530 and 0.407 respectively with surface roughness value. Therefore it can be concluded that the standard deviation of hardness increased when the surface roughness increased