Probabilistic Material Strength Degradation Model for Inconel 718 Components Subjected to High Temperature, Mechanical Fatigue, Creep and Thermal Fatigue Effects

By Bast, Callie Corinne Scheid

Book Id: WPLBN0004288297
Format Type: PDF eBook:
File Size: 2.79 MB
Reproduction Date: 1994-03-01

Title:	Probabilistic Material Strength Degradation Model for Inconel 718 Components Subjected to High Temperature, Mechanical Fatigue, Creep and Thermal Fatigue Effects
Author:	Bast, Callie Corinne Scheid
Volume:	Report-Number: ATCOM-TR-93-A-012-VOL-1; NAS 1.15:109040-VOL-1; NASA-TM-109040-VOL-1; NONP-NASA-SUPPL-DK-94-205049
Language:	English
Subject:	Aircraft Models, Rotary Wings, Velocity Measurement
Collections:	Government Library Collection, Government Library Collection
Historic Publication Date:	1994
Publisher:


Citation APA MLA Chicago Callie Corinne Scheid, B. B. (1994). Probabilistic Material Strength Degradation Model for Inconel 718 Components Subjected to High Temperature, Mechanical Fatigue, Creep and Thermal Fatigue Effects. Retrieved from http://gutenberg.cc/

Description
Description: This thesis presents the on-going development of methodology for a probabilistic material strength degradation model. The probabilistic model, in the form of a postulated randomized multifactor equation, provides for quantification of uncertainty in the lifetime material strength of aerospace propulsion system components subjected to a number of diverse random effects. This model is embodied in the computer program entitled PROMISS, which can include up to eighteen different effects. Presently, the model includes four effects that typically reduce lifetime strength: high temperature, mechanical fatigue, creep, and thermal fatigue. Statistical analysis was conducted on experimental Inconel 718 data obtained from the open literature. This analysis provided regression parameters for use as the model's empirical material constants, thus calibrating the model specifically for Inconel 718. Model calibration was carried out for four variables, namely, high temperature, mechanical fatigue, creep, and thermal fatigue. Methodology to estimate standard deviations of these material constants for input into the probabilistic material strength model was developed. Using the current version of PROMISS, entitled PROMISS93, a sensitivity study for the combined effects of mechanical fatigue, creep, and thermal fatigue was performed. Results, in the form of cumulative distribution functions, illustrated the sensitivity of lifetime strength to any current value of an effect. In addition, verification studies comparing a combination of mechanical fatigue and high temperature effects by model to the combination by experiment were conducted. Thus, for Inconel 718, the basic model assumption of independence between effects was evaluated. Results from this limited verification study strongly supported this assumption.; CASI; Nasa Publication Center: NASA (non Center Specific); Unclassified; No Copyright; Unlimited; Publicly available;; Report-Number: ATCOM-TR-93-A-012-VOL-1; NAS 1.15:109040-VOL-1; NASA-TM-109040-VOL-1; NONP-NASA-SUPPL-DK-94-205049