A Modified Closed Form Energy Based Framework for Axial Isothermal-Mechanical Fatigue Life Assessment for Aluminum 6061-T6

作者：Shen M H Herman^*; Akanda Sajedur R

来源：Journal of Engineering Materials and Technology-Transactions of the ASME, 2015, 137(3): 031007.

DOI：10.1115/1.4030340

• isothermal-mechanical fatigue
• fatigue toughness
• Ramberg-Osgood equation
• stress-life curve

In the present investigation, the applicability of a previously developed closed form energy based framework to predict low cycle fatigue (LCF) life of aluminum 6061-T6 was extended from room temperature to elevated temperature. The three different elevated temperatures considered in the present investigation were 75 degrees C, 100 degrees C, and 125 degrees C which were below the creep activation temperature for aluminum 6061-T6. Like the room temperature life assessment framework, the elevated temperature life assessment framework involved computation of the Ramberg-Osgood cyclic parameters from the average plastic strain range and the average plastic energy obtained from an axial isothermal-mechanical fatigue (IMF) test. The temperature dependent cyclic parameters were computed for 25 degrees C (room temperature), 75 degrees C, and 100 degrees C and then extrapolated to 125 degrees C utilizing functions describing the dependence of the cyclic parameters on temperature. For aluminum 6061-T6, the cyclic parameters were found to decrease with increase of temperature in a quadratic fashion. Furthermore, the present energy based axial IMF framework was found to be able to predict the LCF life of aluminum 6061-T6 at both room and elevated temperatures with excellent accuracy.

• 出版日期2015-7