COMPUTATIONAL MODELLING AND CHARACTERIZATION OF STRESS CONCENTRATION OF LINE PATTERN AT VARIOUS ANGLE ORIENTATION FOR CYCLIC LOADING
Stress concentration is an important parameter when designing mechanical structures because it is typically responsible for fracture, creep, and fatigue failure. In this study, the simulation of Line Pattern of (PLA) Polylactic acid material on ASTM D638 type IV has been chosen to analyze stress concentration for cyclic loading applications. Nine orientations which are 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90° at fixed 50% density has been studied. The simulation was carried out by Sli3er and Solidworks software. The tensile analysis found that the value of displacement did not significantly increase for each orientation but showed some effect when different forced applied. For the stress concentration factor, it showed that the value of stress concentration for all orientation falls in the range of 1.512 until 1.891. The maximum stress concentration value is 1.891 at orientation 40 degrees. Meanwhile, the lowest is 1.512 for orientation 10 degrees. The lowest stress concentration value at 10 degrees might be its flawless and has low discontinuity at this orientation. Besides, the geometry of the line pattern at this orientation is more tendency to horizontal and has the lowest edges compared to other orientation. The fatigue analysis showed the maximum stress level of the specimen is at 634N for orientation 10 and 20 degrees only but not for orientation 30 until 90 degrees. This is because there have maximum stress or break, which consequently cannot sustain longer at the peak load. For fatigue damage analysis, the highest value is 9.69 x 10-2 at orientation 40 degree and the lowest value of fatigue damage is 6.32 x 10-2 at orientation 10 degrees. Overall, it can be concluded the best stress concentration factor of Line pattern PLA material (ASTM D638 type IV) is at orientation 10 degree and for fatigue life, orientation 10 degree has the longest life cycle compared to others orientation. Nevertheless, for cyclic loading application this Line pattern there have a less significant effect towards orientation 10 until 90 degrees.