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Book Thermal Residual Stresses in the Analysis of Fiber Bridged Matrix Crack Growth in Titanium Matrix Composites

Download or read book Thermal Residual Stresses in the Analysis of Fiber Bridged Matrix Crack Growth in Titanium Matrix Composites written by JG. Bakuckas and published by . This book was released on 2006 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this research, thermal residual stresses were incorporated in an analysis of fiber-bridged matrix cracks in unidirectional and cross-ply titanium matrix composites (TMC) containing center holes or center notches. Two TMCs were investigated, namely, SCS-6/Ti-15-3 and SCS-6/Timetal-21S laminates. Experimentally, matrix crack initiation and growth were monitored during tension-tension fatigue tests conducted at room temperature and at an elevated temperature of 200°C. Analytically, thermal residual stresses were included in a fiber bridging (FB) model. The local R-ratio and stress-intensity factor in the matrix due to thermal and mechanical loadings were calculated and used to evaluate the matrix crack growth behavior in the two materials studied. The frictional shear stress term t assumed in this model was used as a curve-fitting parameter to matrix crack growth data. The scatter band in the values of t used to fit the matrix crack growth data was significantly reduced when thermal residual stresses were included in the fiber-bridging analysis. For a given material system, lay-up and temperature, a single value of t was sufficient to analyze the crack growth data. It was revealed in this study that thermal residual stresses are an important factor overlooked in the original FB models.

Book Scientific and Technical Aerospace Reports

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A Methodology to Predict Damage Initiation Damage Growth and Residual Strength in Titanium Matrix Composites

Download or read book A Methodology to Predict Damage Initiation Damage Growth and Residual Strength in Titanium Matrix Composites written by JG. Bakuckas and published by . This book was released on 1996 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this research, a methodology to predict damage initiation, damage growth, fatigue life, and residual strength in titanium matrix composites (TMC) is outlined. Emphasis was placed on micromechanics-based engineering approaches. Damage initiation was predicted using a local effective strain approach. A finite element analysis verified the prevailing assumptions made in the formulation of this model. Damage growth, namely, fiber-bridged matrix crack growth, was evaluated using a fiber bridging (FB) model that accounts for thermal residual stresses. This model combines continuum fracture mechanics and micromechanics analyses yielding stress-intensity factor solutions for fiber-bridged matrix cracks. In the FB model, fibers in the wake of the matrix crack are idealized as a closure pressure, and an unknown constant frictional shear stress is assumed to act along the debond length of the bridging fibers. This frictional shear stress was used as a curve-fitting parameter to the available experimental data. Figure life and post-fatigue residual strength were predicted based on the axial stress in the first intact 0° fiber calculated using the FB model and a three-dimensional finite element analysis.

Book NASA Technical Memorandum

Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Monthly Catalogue United States Public Documents

Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1994-12 with total page 950 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Applied Mechanics Reviews

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1988 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book NASA Langley Scientific and Technical Information Output 1994 Volume 1

Download or read book NASA Langley Scientific and Technical Information Output 1994 Volume 1 written by and published by . This book was released on 1995 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Composite Materials

Download or read book Composite Materials written by Erian A. Armanios and published by ASTM International. This book was released on 1997 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Fatigue Crack Growth Mechanisms in Titanium Metal Matrix Composites

Download or read book Fatigue Crack Growth Mechanisms in Titanium Metal Matrix Composites written by and published by . This book was released on 1996 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report details studies carried out to identify the high temperature fatigue crack growth damage mechanisms in fiber-reinforced titanium metal matrix composites. The report consists of eight separate sections. In the first section, the fatigue and fatigue crack growth characteristics in neat laminates made of Timetal 21S were studied in relation to both temperature and loading frequency effects. The second section deals with the evolution of the thermal residual stresses in the composite when cooling from consolidation temperature or subjecting the composite to thermal cycles. A new mechanical simulation method capable of measuring the induced residual stress on real time basis has been developed in this study. The third section extends this issue to the time-dependent internal stress and strain states of MMCs under the thermomechanical loading conditions. Here, a new micromechanical model employing the four-phase concentric cylinder configuration has been proposed. Based on this model, the time-dependent behavior of continuous fiber reinforced metal matrix composites. It has been evaluated. These results are presented in the fourth section. The fifth, sixth and seventh sections of this report describe the influence of temperature and loading frequency on the crack growth process and suggest a fatigue-creep interactive mechanism acting at the crack tip during high temperature loadings. The last section of the report deals with the determination of the stress evolution in bridging fibers during the fatigue crack growth in SM 1240/Timetal-21S composite using the finite element method. Several parameters affecting this evolution were considered; namely, the process-induced residual stress, the creep characteristics of the matrix layer surrounding the fiber, the test temperature and the loading frequency.

Book Government Reports Announcements Index

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1994 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Modeling Fatigue Crack Growth in Cross Ply Titanium Matrix Composites

Download or read book Modeling Fatigue Crack Growth in Cross Ply Titanium Matrix Composites written by and published by . This book was released on 1993 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Metals Abstracts

Download or read book Metals Abstracts written by and published by . This book was released on 1999-04 with total page 972 pages. Available in PDF, EPUB and Kindle. Book excerpt: