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Fatigue Induced Delamination In Titanium Graphite Hybrid Laminates
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Book Synopsis Fatigue Induced Delamination in Titanium-graphite Hybrid Laminates by : Simon Mark Spearing
Download or read book Fatigue Induced Delamination in Titanium-graphite Hybrid Laminates written by Simon Mark Spearing and published by . This book was released on 1998 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Titanium-graphite hybrid laminates (TiGr) could become an enabling technology for future aerospace vehicles (requiring high operating temperatures and low mass fractions). However, since they are a relatively new material technology, the key damage modes need to be characterized and studied in order to guide material development and structural design. Previous work has identified delamination of the metal layers from the composite plies as a key damage mode. In this paper, results are presented for high temperature (177° C), tension-tension fatigue tests performed on [Ti/0/90/02]s TiGr laminates containing horizontal facesheet seams. Horizontal seams in the titanium facesheets are a likely origination point for delamination. Delamination growth rates were monitored by intermittent direct observation and continuous stiffness monitoring. The cyclic delamination growth rate was found to follow a power law relationship with the applied strain energy release rate, with an exponent of 2. This work provides insight into the delamination growth behavior and provides an empirical starting point for finite element models of delamination growth.
Book Synopsis Mechanics of Fatigue Damage in Titanium-graphite Hybrid Laminates by : Dennis Arthur Burianek
Download or read book Mechanics of Fatigue Damage in Titanium-graphite Hybrid Laminates written by Dennis Arthur Burianek and published by . This book was released on 2001 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: Titanium-graphite hybrid laminates are being developed for high-temperature aerospace applications. Experimental observations have indicated that cracks in the titanium facesheets initiate at free edges as well as in areas of high stress concentration, such as holes and notches and that a delaminated region between the facesheet and the intact plies develops and propagates in the wake of the facesheet crack. This thesis experimentally and analytically evaluates the facesheet crack and delamination growth behavior of TiGr laminates. The delamination growth behavior is studied by isolating delamination growth using TiGr specimens with facesheet seams. The growth rate of delamination from facesheet seams is related via a power law to the applied strain energy release rate. It is shown that elevated temperatures significantly increase the growth rate of facesheet delamination. The facesheet crack growth behavior in TiGr laminates was measured experimentally and compared to model predictions. It is shown that the crack growth rate in TiGr facesheets is significantly lower for TiGr laminates as compared to monolithic titanium. After an initial decrease in crack growth rate, the crack propagates at a constant rate while the crack growth rate for monolithic titanium increases as the crack extends. A three-dimensional finite element model was implemented that captured the experimental crack growth trends without any additional tuning parameters. A global, bridged-crack model was not accurate in predicting the facesheet crack growth behavior of TiGr laminates. The bridged-crack model failed because it did not capture the details of the bridging stresses and delamination in the vicinity of the crack tip. In contrast to the delamination growth from facesheet seams, it was shown that elevated temperatures did not significantly affect the growth rate of the titanium facesheet crack. Future efforts to model composite damage growth using global modeling approach must validate the model to ensure that all of the necessary parameters are captured.
Book Synopsis Delamination Growth from Facesheet Seams in Cross-ply Titanium Graphite Hybrid Laminates by : Dennis Arthur Burianek
Download or read book Delamination Growth from Facesheet Seams in Cross-ply Titanium Graphite Hybrid Laminates written by Dennis Arthur Burianek and published by . This book was released on 2000 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: A test program was conducted to study the fatigue delamination behavior of titanium-graphite hybrid laminates (TiGr) with seams in the titanium facesheets. Tension fatigue experiments were conducted at -18° C, 210 C (room temperature), 930 C, and at 177°C on cross-ply, [Ti/0/90/02 , Titanium-Graphite hybrid laminates (TiGr). The delamination growth rate obeyed a power law function of the applied strain energy release rate range. The prefactor on the power law function showed a strong dependence on temperature. In addition, experiments were performed on laminates with 30° plies. The primary damage mode in this lay-up was edge delamination of the interior plies. Analysis of the [Ti/0/90/ O], family of laminates indicated that for angles greater than 10°, edge delamination would be the dominant damage mode in coupon specimens..
Book Synopsis Delamination Growth from Facesheet Seams in Titanium-graphite Hybrid Laminates by : Dennis Arthur Burianek
Download or read book Delamination Growth from Facesheet Seams in Titanium-graphite Hybrid Laminates written by Dennis Arthur Burianek and published by . This book was released on 1999 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: A test program was conducted to study the fatigue behavior of titanium-graphite hybrid laminates (TiGr) with seams in the titanium facesheets. Experiments were conducted at 21° C (room temperature) and at 177°C on cross-ply TiGr laminates. It was determined that the delamination growth rate obeyed a power law function of the applied strain energy release rate. In addition, experiments were performed on laminates with ±30° plies. The primary damage mode in the alternate lay-up was edge delamination of the interior plies. Analysis of the [Ti/0/90/±[theta]]s, family of laminates indicated that for angles greater than 10°, edge delamination would be the dominant damage mode.
Book Synopsis Fatigue Damage in Titanium Graphite Hybrid Laminates by : Dennis Arthur Burianek
Download or read book Fatigue Damage in Titanium Graphite Hybrid Laminates written by Dennis Arthur Burianek and published by . This book was released on 1998 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hybrid laminates could become an enabling technology for future high-temperature, low mass fraction aerospace vehicles. However, since they are a relatively new material technology, research needs to be conducted to characterize the key damage modes to guide material development and structural design. In this research program, high temperature, tension-compression fatigue tests were performed on TiGr laminates. Fatigue life data were collected for specimens at several percentages of open hole tension strength. A series of specimens were tested and analyzed using cross-sectioning and microscopy to quantify the damage progression sequence in the laminates. Stiffness measurements were taken during fatigue cycling and were correlated with damage state and residual strength after cycling. The key damage modes were identified as ply splitting, facesheet cracking and facesheet delamination. A comparison was made between the ply splits in TiGr and similar splitting observed in 00/900 cross-ply PMC laminates which showed that the growth rate of the splits was similar to that of splits in non-hybrid PMC laminates. The titanium facesheet cracking was consistent with the applied stress levels and the fatigue behavior of monolithic titanium. Delamination is the dominant damage mode for stiffness reduction. Extensive delamination is consistent with the high strain energy release rate between the facesheet and the core. This work provides insight as to the key damage modes and factors controlling the progression and provides recommendations for critical areas for future investigation and material development.
Book Synopsis Interacting Damage Modes in Titanium-graphite Hybrid Laminates by : Dennis Arthur Burianek
Download or read book Interacting Damage Modes in Titanium-graphite Hybrid Laminates written by Dennis Arthur Burianek and published by . This book was released on 2001 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental and analytical investigation was conducted of the growth under cyclic loading of face-sheet cracks coupled with delaminations in Titanium-graphite hybrid laminates. A 3-D finite element model was developed to obtain the stress-intensity factor for the titanium face-sheet crack as a function of the material properties, ply thicknesses, specimen geometry and delamination shape. The results for the stress-intensity factor were compared to a 2-D finite element model and a cohesive zone/bridged crack model. Significant differences were identified indicating that for this problem it is essential to use a full 3-D analysis. The model was applied to experimental data for three laminates (Ti/0/90/02)s, (Ti/90/0/90 2 ) 2 and (Ti/0/90/30)s. An independently-calibrated Paris Law was used to describe the fatigue crack growth behavior of the face-sheets. A good description of the experimental data was obtained for the first two laminates, with a slightly less-good description for the third. This poorer fit was attributed to the presence of additional damage modes in the laminate containing 30' plies. In all cases the face-sheet cracks were found to asymptote to a steady state (crack length-independent) growth regime, which was predicted by the 3-D finite element model. Crack opening displacement profiles measured experimentally were compared with those predicted by the finite element model. Good agreement was demonstrated, indicating that the FE model correctly modeled the load transfer mechanisms around the crack.
Book Synopsis Recent Developments in Durability Analysis of Composite Systems by : H. Dardon
Download or read book Recent Developments in Durability Analysis of Composite Systems written by H. Dardon and published by CRC Press. This book was released on 2022-01-26 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers from these proceedings address experimental and analytical methods for the characterization and analysis of modern composite and adhesive systems. They have been produced to provide understanding that can be used to design safe, reliable engineering components.
Book Synopsis American Society of Composites, Fourteenth International Conference Proceedings by : Amer Society Composi
Download or read book American Society of Composites, Fourteenth International Conference Proceedings written by Amer Society Composi and published by CRC Press. This book was released on 1999-10-25 with total page 1030 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conference proceedings of the Fourteenth American Society for Composites held on the September 27-29 1999 at the Holiday Inn-1675 Conference Centre, Fairborn, Ohio.
Book Synopsis Mixed-mode Strain-energy-release Rate Effects on Edge Delamination of Composites by : Kevin T. O'Brien
Download or read book Mixed-mode Strain-energy-release Rate Effects on Edge Delamination of Composites written by Kevin T. O'Brien and published by . This book was released on 1983 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Application of a Stochastic Model for Fatigue-Induced Delamination Growth in Graphite/Epoxy Laminates by : RB. Bucineill
Download or read book Application of a Stochastic Model for Fatigue-Induced Delamination Growth in Graphite/Epoxy Laminates written by RB. Bucineill and published by . This book was released on 1998 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: A stochastic model is used to predict the growth of delamination in graphite/epoxy laminates subjected to cyclic loading. The advantage of this model is that both the mean and variance associated with the growth of delamination is predicted. Understanding and predicting the variability associated with the delamination growth process is essential to the estimation of the reliability of composite structures. The empirical nature of the model has been minimized through the introduction of fracture mechanics parameters into the stochastic model. This has been accomplished by assuming that the mean of the stochastic model is represented by a fracture mechanics power law based on strain energy release rate. The applicability of the model is demonstrated through an experimental program that utilizes three laminate geometries. The results of the experimental evaluation illustrate the ability of the model to predict both the mean and variance of the delamination growth process in composite laminates subjected to cyclic loading.
Book Synopsis Fatigue Damage Mechanisms of Advanced Hybrid Titanium Composite Laminates by : Donald William Rhymer
Download or read book Fatigue Damage Mechanisms of Advanced Hybrid Titanium Composite Laminates written by Donald William Rhymer and published by . This book was released on 1999 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721280735 Total Pages :24 pages Book Rating :4.2/5 (87 download)
Book Synopsis Fatigue Damage Mechanisms in Advanced Hybrid Titanium Composite Laminates by : National Aeronautics and Space Administration (NASA)
Download or read book Fatigue Damage Mechanisms in Advanced Hybrid Titanium Composite Laminates written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-19 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hybrid Titanium Composite Laminates (HTCL) are a type of hybrid composite laminate with promise for high-speed aerospace applications, specifically designed for improved damage tolerance and strength at high-temperature (350 F, 177 C). However, in previous testing, HTCL demonstrated a propensity to excessive delamination at the titanium/PMC interface following titanium cracking. An advanced HTCL has been constructed with an emphasis on strengthening this interface, combining a PETI-5/IM7 PMC with Ti-15-3 foils prepared with an alkaline-perborate surface treatment. This paper discusses how the fatigue capabilities of the "advanced" HTCL compare to the first generation HTCL which was not modified for interface optimization, in both tension-tension (R = 0.1) and tension-compression (R=-0.2). The advanced HTCL under did not demonstrate a significant improvement in fatigue life, in either tension-tension or tension-compression loading. However, the advanced HTCL proved much more damage tolerant. The R = 0.1 tests revealed the advanced HTCL to increase the fatigue life following initial titanium ply damage up to 10X that of the initial HTCL at certain stress levels. The damage progression following the initial ply damage demonstrated the effect of the strengthened PMC/titanium interface. Acetate film replication of the advanced HTCL edges showed a propensity for some fibers in the adjacent PMC layers to fail at the point of titanium crack formation, suppressing delamination at the Ti/PMC interface. The inspection of failure surfaces validated these findings, revealing PMC fibers bonded to the majority of the titanium surfaces. Tension compression fatigue (R = -0.2) demonstrated the same trends in cycles between initial damage and failure, damage progression, and failure surfaces. Moreover, in possessing a higher resistance to delamination, the advanced HTCL did not exhibit buckling following initial titanium ply cracking under compression unlike the initial HTCL
Book Synopsis Modeling of Facesheet Crack Growth in Titanium-graphite Hybrid Laminates by : Dennis Arthur Burianek
Download or read book Modeling of Facesheet Crack Growth in Titanium-graphite Hybrid Laminates written by Dennis Arthur Burianek and published by . This book was released on 2001 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Titanium-graphite hybrid composite laminates exhibit a coupled damage growth mode of facesheet cracking and delamination. Part I of this work modeled the growth of the coupled damage mode. Fatigue experiments were conducted on single edge notch tension specimens to measure the crack growth rate. This paper compares the model predictions with experimental data. The three-dimensional finite element model successfully captured the damage growth behavior for two of the lay-ups ([Ti/0/90/02]s and [Ti/90/0/902]s) in the experimental program. However, in a third lay-up, [Ti/0/90/±30]s, the underlying damage modes were found to be sufficiently different than the other two lay-ups and the model did not capture the steady-state growth behavior. The effects of temperature and specimen size were also investigated for TiGr laminates. Except for the effects of the load ratio, elevated temperatures did not affect the crack growth rate significantly. For wider specimens, the steady-state fatigue crack growth behavior was similar to the narrow specimens, indicating that the steady state face sheet crack growth behavior is independent of specimen size. KeyWords Hybrid laminates, fatigue crack growth, crack bridging, virtual crack closure, TiGr.
Book Synopsis Durability of Titanium-graphite Hybrid Laminates by : Dennis Arthur Burianek
Download or read book Durability of Titanium-graphite Hybrid Laminates written by Dennis Arthur Burianek and published by . This book was released on 1999 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental results are presented for elevated temperature (177° C), tension-compression fatigue tests performed on titanium-graphite (TiGr) hybrid laminates containing open holes. The key damage modes were identified as 0° ply splitting, facesheet cracking, and facesheet delamination. The growth of damage during fatigue resulted in large reductions of the local stiffness adjacent to the hole. This stiffness reduction was predominantly due to delamination of the facesheet from the polymer matrix composite core and showed a significant temperature dependence. Using a simple one-dimensional model it was shown that the delamination growth rates depend on the applied loading according to a "Paris" law, with an exponent of 1.9 on the cyclic strain energy release rate. This observation was substantiated by observations of delaminations growing in isolation in specimens containing facesheet seams.
Book Synopsis Proceedings of the American Society for Composites ... Technical Conference by :
Download or read book Proceedings of the American Society for Composites ... Technical Conference written by and published by . This book was released on 1999 with total page 1032 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722799052 Total Pages :56 pages Book Rating :4.7/5 (99 download)
Book Synopsis Tension Fatigue Analysis and Life Prediction for Composite Laminates by : National Aeronautics and Space Administration (NASA)
Download or read book Tension Fatigue Analysis and Life Prediction for Composite Laminates written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-16 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: A tension fatigue life prediction methodology for composite laminates is presented. Tension fatigue tests were conducted on quasi-isotropic and orthotropic glass epoxy, graphite epoxy, and glass/graphite epoxy hybrid laminates. Edge delamination onset data were used to generate plots of strain energy release rate as a function of cycles to delamination onset. These plots were then used along with strain energy release rate analyses of delaminations initiating at matrix cracks to predict local delamination onset. Stiffness loss was measured experimentally to account for the accumulation of matrix cracks and for delamination growth. Fatigue failure was predicted by comparing the increase in global strain resulting from stiffness loss to the decrease in laminate failure strain resulting from delaminations forming at matrix cracks through the laminate thickness. Good agreement between measured and predicted lives indicated that the through-thickness damage accumulation model can accurately describe fatigue failure for laminates where the delamination onset behavior in fatigue is well characterized, and stiffness loss can be monitored in real time to account for damage growth. Obrien, T. K. and Rigamonti, M. and Zanotti, C. Langley Research Center...
Book Synopsis The Effect of Loading Parameters on Fatigue of Composite Laminates: Part 3 by :
Download or read book The Effect of Loading Parameters on Fatigue of Composite Laminates: Part 3 written by and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The long-term mechanical fatigue of quasi-isotropic graphite/epoxy laminates was investigated to determine the influence of loading parameters on impact-induced delamination growth during constant-amplitude and spectrum fatigue loading. Based on the test results, recommendations for fatigue design of composite laminates in the presence of barely visible impact damage (BVID) are suggested.
