Download or read book Modeling Fatigue Crack Growth in Cross Ply Titanium Matrix Composites written by J. G. Bakuckas and published by . This book was released on 1993 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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:
Download or read book Titanium Matrix Composites written by Shankar Mall and published by CRC Press. This book was released on 1997-12-02 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 discuss the following topics: monotonic response, micromechanical theories, fiber-matrix interface, fatigue failure mechanisms, fatigue and thermomechanical fatigue life prediction, creep behavior, fatigue crack growth, notch strength, and micromechanical analysis and modeling. Annotation copyrighted by Book News, Inc., Portland, OR
Download or read book Titanium Matrix Composites Under Fatigue Crack Growth Conditions and a Model Material Approach written by Felipe G. Elizondo (Jr) and published by . This book was released on 1996 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Life Prediction Methodology for Titanium Matrix Composites written by W. Steven Johnson and published by ASTM International. This book was released on 1996 with total page 625 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book An Approach to Include Interfacial Wear Effects in Modeling Fatigue Crack Growth of Titanium Matrix Composites written by BM. Hillberry and published by . This book was released on 1998 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: An approach has been developed that includes the effects of interfacial wear on the fiber-bridging behavior of titanium matrix composites during fatigue crack propagation. This approach uses a Coulomb friction-based fiber-bridging model in which the effect of fiber surface roughness on the clamping stress between the fiber and matrix is included. A previously developed wear model has been incorporated into this bridging model as a means to determine the reduction of the fiber surface roughness amplitude during fatigue cycling. As the roughness decreases, its contribution to the clamping stress also decreases, resulting in a lower interfacial shear stress. In order to include this effect in model fatigue crack growth rates, the combined Coulomb friction and wear models have been applied to a discrete composite model formulation. Crack growth predictions were then performed using a single set of input parameters by allowing the fiber surface roughness to decrease due to wear over a discrete increment of fatigue crack geometry based on bridging conditions determined by the composite model. These predictions correlated very well with experimental results for different loading conditions, especially those at relatively high crack growth rates.
Download or read book Modeling the Crack Growth Rates of a Titanium Matrix Composite Under Thermomechanical Fatigue written by D. Blatt and published by . This book was released on 1996 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The crack growth characteristics of a 4-ply, unidirectional, titanium matrix composite, SCS-6/Ti-6Al-2Sn-4Zr-2Mo, subjected to thermomechanical fatigue were investigated. A linear summation model was developed to predict the isothermal and thermomechanical fatigue (TMF) crack growth rates of the composite. The linear summation approach assumes the total fatigue crack growth rate is a combination of a cycle-dependent and a time-dependent component. To assist the modeling effort, a series of isothermal, in-phase, and out-of-phase crack growth tests were conducted. The test temperatures ranged from 150‡C to 538‡C and the fastest thermal frequency was 0.0083 Hz. With the exception of the 150‡C isothermal test, the model was able to correlate all the baseline fatigue crack growth test data between ?K of 50 to 90 MPa ?m. In addition, the model was able to predict the fatigue crack growth rate of a proof test which involved a continual change in temperature range and load range to produce a constant crack growth rate. The proof test began under isothermal conditions at the maximum temperature and ended under in-phase TMF conditions.
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:
Download or read book Fatigue Crack Growth Behavior of a Titanium Matrix Composite Under Thermomechanical Loading written by and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of Fiber Bridging Models to Fatigue Crack Growth in Unidirectional Titanium Matrix Composites written by and published by . This book was released on 1992 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Prediction of Matrix Fatigue Crack Initiation from Notches in Titanium Matrix Composites written by DJ. Herrmann and published by . This book was released on 1996 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fatigue crack initiation from notches in titanium matrix composites (TMCs) is of interest in the design of TMC structures. A model is presented for predicting the fatigue crack initiation life of longitudinal, transverse, and symmetric cross-ply laminates using the strain-life behavior of the matrix material. The effective strain parameter, ??eff, proposed by Hillberry and Johnson is used to account for the residual stress state imposed during composite processing. Since the effective strain parameter requires knowledge of the local residual and applied strain in the matrix, methods for calculating these strains are developed. Model predictions were verified with crack initiation tests of [0]4, [90]4, and [0/90]s SCS-6/TIMETAL 21S center-hole specimens at room temperature and [04/ ̄90]s SCS-6/Ti-15-3 center-hole specimens at 300 and 550°C.
Download or read book Observations of Fatigue Crack Initiation and Damage Growth in Notched Titanium Matrix Composites written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-09 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose was to characterize damage initiation and growth in notched titanium matrix composites at room temperature. Double edge notched or center open hole SCS-6/Ti-15-3 specimens containing 0 deg plies or containing both 0 and 90 deg plies were fatigued. The specimens were tested in the as-fabricated (ASF) and in heat-treated conditions. A local strain criterion using unnotched specimen fatigue data was successful in predicting fatigue damage initiation. The initiation stress level was accurately predicted for both a double edge notched unidirectional specimen and a cross-plied center hole specimen. The fatigue produced long multiple cracks growing from the notches. These fatigue cracks were only in the matrix material and did not break the fibers in their path. The combination of matrix cracking and fiber/matrix debonding appears to greatly reduce the stress concentration around the notches. The laminates that were heat treated showed a different crack growth pattern. In the ASF specimens, matrix cracks had a more tortuous path and showed considerable more crack branching. For the same specimen geometry and cyclic stress, the (0/90/0) laminate with a hole had far superior fatigue resistance than the matrix only specimen with a hole. Naik, R. A. and Johnson, W. S. Langley Research Center RTOP 505-63-01-05...
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.
Download or read book Fatigue Damage in Cross ply Titanium Metal Matrix Composites Containing Center Holes written by and published by . This book was released on 1992 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Specimen Orientation of the Fatigue Crack Growth Resistance of Cross ply TI 6AL 4V SCS 6 Metal matrix Composites written by A. Yasmin and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of Fiber Bridging Models to Fatigue Crack Growth in Unidirectional Titanium Matrix Composites written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-06 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several fiber bridging models were reviewed and applied to study the matrix fatigue crack growth behavior in center notched (0)(sub 8) SCS-6/Ti-15-3 and (0)(sub 4) SCS-6/Ti-6Al-4V laminates. Observations revealed that fatigue damage consisted primarily of matrix cracks and fiber matrix interfacial failure in the (0)(sub 8) SCS-6/Ti-15-3 laminates. Fiber-matrix interface failure included fracture of the brittle reaction zone and cracking between the two carbon rich fiber coatings. Intact fibers in the wake of the matrix cracks reduce the stress intensity factor range. Thus, an applied stress intensity factor range is inappropriate to characterize matrix crack growth behavior. Fiber bridging models were used to determine the matrix stress intensity factor range in titanium metal matrix composites. In these models, the fibers in the wake of the crack are idealized as a closure pressure. An unknown constant frictional shear stress is assumed to act along the debond or slip length of the bridging fibers. The frictional shear stress was used as a curve fitting parameter to available data (crack growth data, crack opening displacement data, and debond length data). Large variations in the frictional shear stress required to fit the experimental data indicate that the fiber bridging models in their present form lack predictive capabilities. However, these models provide an efficient and relatively simple engineering method for conducting parametric studies of the matrix growth behavior based on constituent properties. Bakuckas, J. G., Jr. and Johnson, W. S. Langley Research Center...
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.
