Proposed Framework for Thermomechanical Fatigue (TMF) Life Prediction of Metal Matrix Composites (MMCs) PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Proposed Framework for Thermomechanical Fatigue (TMF) Life Prediction of Metal Matrix Composites (MMCs) PDF full book. Access full book title Proposed Framework for Thermomechanical Fatigue (TMF) Life Prediction of Metal Matrix Composites (MMCs) by VK. Arya. Download full books in PDF and EPUB format.
Author: VK. Arya
Publisher:
ISBN:
Category : Alloys
Languages : en
Pages : 19
Get Book Here
Book Description
The framework of a mechanics of materials model is proposed for thermomechanical fatigue (TMF) life prediction of unidirectional, continuous-fiber metal matrix composites (MMCs). Axially loaded MMC test samples are analyzed as structural components whose fatigue lives are governed by local stress-strain conditions resulting from combined interactions of the matrix, interfacial layer, and fiber constituents. The metallic matrix is identified as the vehicle for tracking fatigue crack initiation and propagation. The proposed framework has three major elements. First, TMF flow and failure characteristics of in situ matrix material are approximated from tests of unreinforced matrix material, and matrix TMF life prediction equations are numerically calibrated. The macrocrack initiation fatigue life of the matrix material is divided into microcrack initiation and microcrack propagation phases. Second, the influencing factors created by the presence of fibers and interfaces are analyzed, characterized, and documented in equation form. Some of the influences act on the microcrack initiation portion of the matrix fatigue life, others on the microcrack propagation life, while some affect both. Influencing factors include coefficient of thermal expansion mismatch strains, residual (mean) stresses, multiaxial stress states, off-axis fibers, internal stress concentrations, multiple initiation sites, nonuniform fiber spacing, fiber debonding, interfacial layers and cracking, fractured fibers, fiber deflections of crack fronts, fiber bridging of matrix cracks, and internal oxidation along internal interfaces. Equations exist for some, but not all, of the currently identified influencing factors. The third element is the inclusion of overriding influences such as maximum tensile strain limits of brittle fibers that could cause local fractures and ensuing catastrophic failure of surrounding matrix material. Some experimental data exist for assessing the veracity of the proposed framework.
Author: VK. Arya
Publisher:
ISBN:
Category : Alloys
Languages : en
Pages : 19
Get Book Here
Book Description
The framework of a mechanics of materials model is proposed for thermomechanical fatigue (TMF) life prediction of unidirectional, continuous-fiber metal matrix composites (MMCs). Axially loaded MMC test samples are analyzed as structural components whose fatigue lives are governed by local stress-strain conditions resulting from combined interactions of the matrix, interfacial layer, and fiber constituents. The metallic matrix is identified as the vehicle for tracking fatigue crack initiation and propagation. The proposed framework has three major elements. First, TMF flow and failure characteristics of in situ matrix material are approximated from tests of unreinforced matrix material, and matrix TMF life prediction equations are numerically calibrated. The macrocrack initiation fatigue life of the matrix material is divided into microcrack initiation and microcrack propagation phases. Second, the influencing factors created by the presence of fibers and interfaces are analyzed, characterized, and documented in equation form. Some of the influences act on the microcrack initiation portion of the matrix fatigue life, others on the microcrack propagation life, while some affect both. Influencing factors include coefficient of thermal expansion mismatch strains, residual (mean) stresses, multiaxial stress states, off-axis fibers, internal stress concentrations, multiple initiation sites, nonuniform fiber spacing, fiber debonding, interfacial layers and cracking, fractured fibers, fiber deflections of crack fronts, fiber bridging of matrix cracks, and internal oxidation along internal interfaces. Equations exist for some, but not all, of the currently identified influencing factors. The third element is the inclusion of overriding influences such as maximum tensile strain limits of brittle fibers that could cause local fractures and ensuing catastrophic failure of surrounding matrix material. Some experimental data exist for assessing the veracity of the proposed framework.
Author: Gary R. Halford
Publisher:
ISBN:
Category : Metallic composites
Languages : en
Pages : 20
Get Book Here
Book Description
Author: Michael J. Verrilli
Publisher: ASTM International
ISBN: 080312001X
Category :
Languages : en
Pages : 382
Get Book Here
Book Description
Author: W. Steven Johnson
Publisher: ASTM International
ISBN: 0803120397
Category : Metallic composites
Languages : en
Pages : 625
Get Book Here
Book Description
Papers presented at the March 1994 symposium are organized into five sections that progress from basic understanding of mechanical damage mechanisms and environmental effects to life prediction methodology. Five papers discuss the interplay between interfacial strength, residual thermal stresses, an
Author: Huseyin Sehitoglu
Publisher: ASTM International
ISBN: 0803118716
Category : AIIoys
Languages : en
Pages : 259
Get Book Here
Book Description
Author: Huseyin Sehitoglu
Publisher: ASTM International
ISBN: 0803128533
Category : Alloys
Languages : en
Pages : 339
Get Book Here
Book Description
Author: RW. Neu
Publisher:
ISBN:
Category : Elevated temperature
Languages : en
Pages : 23
Get Book Here
Book Description
Parameters and models to correlate the cycles to failure of a unidirectional metal matrix composite (SCS-6/Timetal 21S) undergoing thermal and mechanical loading are examined. Three different cycle types are considered: out-of-phase thermomechanical fatigue (TMF), in-phase TMF, and isothermal fatigue. A single parameter based on either the fiber or matrix behavior is shown not to correlate the cycles to failure of all the data. Two prediction methods are presented that assume that life may be dependent on at least two fatigue damage mechanisms and therefore consist of two terms. The first method, the linear life fraction model, shows that by using the response of the constituents, the life of these different cycle types are better correlated using two simple empirical relationships: one describing the fatigue damage in the matrix and the other fiber-dominated damage. The second method, the dominant damage model, is more complex but additionally brings in the effect of the environment. This latter method improves the predictions of the effects of the maximum temperature, temperature range, and frequency, especially under out-of-phase TMF and isothermal fatigue. The steady-state response of the constituents is determined using a 1-D micromechanics model with viscoplasticity. The residual stresses due to the CTE mismatch between the fiber and matrix during processing are included in the analysis.
Author: Shankar Mall
Publisher: CRC Press
ISBN: 1000725472
Category : Technology & Engineering
Languages : en
Pages : 482
Get Book Here
Book Description
A review and summary of advancements related to mechanical behavior and related mechanics issues of titanium matrix composites (TMCs), a class of high-temperature materials useful in the propulsion and airframe components in advanced aerospace systems. After an introduction to TMCs, different authors review and summarise the advancements related to mechanical behavior and related mechanics issues of TMCs.
Author: Calcaterra, JR.
Publisher:
ISBN:
Category : Composite materials
Languages : en
Pages : 23
Get Book Here
Book Description
Several methodologies have been developed to predict the lives of titanium matrix composites (TMCs) subjected to thermomechanical fatigue (TMF). This paper reviews and compares five life prediction models developed at NASA-LaRC, Wright Laboratories, and Clarkson University. The models developed at NASA-LaRC and Clarkson University are based on a single parameter, the fiber stress in the load-carrying, or 0°, direction. The two other models, both developed at Wright Labs, are multi-parameter models. These can account for long-term damage, which is beyond the scope of the single-parameter models, but this benefit is offset by the additional complexity of the methodologies. Each of the methodologies was used to model data generated at NASA-LeRC, Wright Labs, and Georgia Tech for the SCS-6/Timetal 21-S material system. Viscoply, a micromechanical stress analysis code, was used to determine the constituent stress state for each test and was used for each model to maintain consistency. The predictive capabilities of the models are compared, and the ability of each model to accurately predict the responses of tests dominated by differing damage mechanisms is addressed.
Author: S. S. Manson
Publisher: ASM International
ISBN: 1615030549
Category : Science
Languages : en
Pages : 277
Get Book Here
Book Description
From concept to application, this book describes the method of strain-range partitioning for analyzing time-dependent fatigue. Creep (time-dependent) deformation is first introduced for monotonic and cyclic loading. Multiple chapters then discuss strain-range partitioning in details for multi-axial loading conditions and how different loading permutations can lead to different micro-mechanistic effects. Notably, the total-strain method of strain-range partitioning (SRP) is described, which is a methodology that sees use in several industries. Examples from aerospace illustrate applications, and methods for predicting time-dependent metal fatigue are critiqued.
