Design of an Experiment to Analyze Modal Parameters in a Crack and Without Crack Conditions in the Presence of Thermal and Mechanical Vibration

Abstract

AbstractVibration fatigue is a common phenomenon in structural dynamic due to thermal and mechanical loads. This paper designed an experimental method to access the impact of temperatures on the vibration behavior of crack and without crack beam. This experimental design was considered without crack and with a crack of three crack depth 0.25 mm, 0.5 mm, and 1 mm. To analyze the effect of temperatures, three cases of ramping of temperatures were considered. The first case ramped at 2 °C/min allowing the temperature to increase in a slow and steady state to reach the desired temperature. The second case allotted the temperature to increase at a moderate rate at 5 °C/min. In the third case, the temperature was allowed to increase rapidly at a rate of 8 °C/min. This controlled rate of heating the beam was monitor from a PID temperature controller. The experimental results showed that different ramped of temperature has some influence on modal parameters. The temperature ramped at 2 °C/min has more impact on modal parameters than ramped at 5 °C/min and 8 °C/min. While this effect is negligible for lower temperatures, but it is obvious at elevated temperatures. This suggested heating the beam at different rates affects vibration response. Thus, this indicated the heating rate can make some effect on the vibration response measurement of mechanical structures.KeywordsThermal analysisVibration fatigueVibration testingModal analysisFracture mechanicsStructural response