Numerical and Experimental Investigations on Flexural Fatigue Behaviour of
Glass/Epoxy Composite and SAE 1040 Steel Tubes for Automotive Applications 2019-26-0317
Fatigue life of automotive structures depends on static strength, range of stress, mode of cycling, load histories, and environmental conditions. i.e. temperature, humidity, moisture etc. This paper presents results on the flexural fatigue life and damage accumulation of SAE 1040 steel and Glass/Epoxy composite automotive material tubes at room temperature in the dry condition. The correlation between their structure, geometry and fatigue behaviour is a subject area that needs to be understood and investigated in the automotive applications like anti-roll bars and tubes.
For comparative durability studies, the flexural static and fatigue tests were carried out on test specimens under constant amplitude with a sinusoidal waveform for a frequency of 3 Hz. Flexural fatigue loading conditions were analyzed at different load levels from 30% to 87 % of the material ultimate flexural strength. Fatigue tests were stopped after 1 million cycles even if fracture or damage were not observed. Experimental S-N curves of SAE 1040 steel and Glass/Epoxy composite tube specimens were obtained under constant amplitude loading conditions. Fatigue properties obtained from specimen testing are then used in life predictions using the S-N approach. The predicted lives and damage evaluated from experimental and Finite Element codes using ANSYS software are found to be in good agreement. The fracture features of the steel and composite tubes observed with a Scanning Electron Microscope (SEM) were observed to be in agreement with the obtained test data and predicted mechanisms.
Keywords: Static flexure, Flexural Fatigue, FE analysis, Glass/Epoxy composite tube, SAE 1040 tube, Fatigue life predictions.
Amol Bhanage, Padmanabhan Krishnan
SMEC,Vellore Institute of Technology
Symposium on International Automotive Technology 2019