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Interacting Damage Modes In Titanium Graphite Hybrid Laminates
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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 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 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 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 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 The Virtual Crack Closure Technique: History, Approach and Applications by : Ronald Krueger
Download or read book The Virtual Crack Closure Technique: History, Approach and Applications written by Ronald Krueger and published by . This book was released on 2002 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the virtual crack closure technique is presented. The approach used is discussed, the history summarized, and insight into its applications provided. Equations for two-dimensional quadrilateral elements with linear and quadratic shape functions are given. Formula for applying the technique in conjuction with three-dimensional solid elements as well as plate/shell elements are also provided. Necessary modifications for the use of the method with geometrically nonlinear finite element analysis and corrections required for elements at the crack tip with different lengths and widths are discussed. The problems associated with cracks or delaminations propagating between different materials are mentioned briefly, as well as a strategy to minimize these problems. Due to an increased interest in using a fracture mechanics based approach to assess the damage tolerance of composite structures in the design phase and during certification, the engineering problems selected as examples and given as references focus on the application of the technique to components made of composite materials.
Book Synopsis Adaptive Structures, Eighth Japan/US Conference Proceedings by : Golam M. Newaz
Download or read book Adaptive Structures, Eighth Japan/US Conference Proceedings written by Golam M. Newaz and published by CRC Press. This book was released on 2019-11-28 with total page 1068 pages. Available in PDF, EPUB and Kindle. Book excerpt: First published in 1998. A collection of papers presented at the Proceedings of the Eighth Japan-U.S. Conference On Composite Materials, SEPTEMBER 24 to 25 , 1998. The conference is organized by Wayne State University and American Society for Composites in cooperation with U.S. Organizing Committee and the Japanese Organizing Committee. Since the Seventh Meeting in Kyoto in 1995, this meeting brings together accomplished composite researchers between the two countries to share latest developments and advances in the field. The scope of the current conference ranges over all aspects of composite materials with some emphasis on infrastructure applications of composites. Key areas in composites are covered by 110 papers with 35 presentations from Japan.
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 SME Technical Paper by : Society of Manufacturing Engineers
Download or read book SME Technical Paper written by Society of Manufacturing Engineers and published by . This book was released on 2003 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Advanced Fatigue Damage Development in Graphite Epoxy Laminates by : Russell Douglas Jamison
Download or read book Advanced Fatigue Damage Development in Graphite Epoxy Laminates written by Russell Douglas Jamison and published by . This book was released on 1982 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of an experimental investigation of damage development in T300/5208 graphite epoxy laminates subjected to tension-tension cyclic loading are reported. The concept of laminate stiffness reduction as a damage analogue is shown to be a valuable means of test control and damage interpretation. The relationship between stiffness and number of cycles is shown to be unique for each laminate type studied, each possessing three distinct stages, but markedly different among the laminate types. By using two complementary nondestructive evaluation (NDE) techniques, edge replication and penetrant-enhanced stereo X- ray radiography along with a method for deploying fatigue-damaged specimens, the stages of stiffness reduction were found to correspond variously to the predominance of matrix cracking or delamination or interactions of these matrix damage modes. A number of subordinate matrix damage modes including interior delamination, microcracking, and longitudinal splitting are identified with the matrix cracks which produce them.
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..
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 Experimental and Numerical Methods for Characterization of Impact Damage in Titanium-Graphite Laminates by : Stefan P. Hovik
Download or read book Experimental and Numerical Methods for Characterization of Impact Damage in Titanium-Graphite Laminates written by Stefan P. Hovik and published by . This book was released on 2019 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: TiGr (Titanium-Graphite) is a relatively new aerospace material system composed of layers of titanium alloy and graphite-reinforced thermoplastic. This material is in a class of materials called FMLs (Fiber-Metal-Laminates) which are characterized by high stiffness, fatigue resistance, and strength-to-weight ratios when compared to traditional composites. One of the particularly advantageous properties of TiGr is its damage tolerance; specifically its resistance to impact damage. While traditional graphite composites may sustain significant sub-surface impact damage in the form of delamination, fiber breakage, and matrix cracking that can be very difficult to detect, TiGr sustains damage primarily by absorbing energy in the form of plastic metal deformation and re-direction of impact energy into the plane of the metallic layers. This is useful both in that the damage is readily detectable by visual inspection, characterized by local plastic yielding, and that the mechanism for energy dissipation allows for absorption of greater energy with less effect to residual compressive strength compared to traditional graphite fiber composites. A finite element modelling method has been developed to show failure mechanism dependence on impact energy, layup sequence, and titanium thickness, and have been validated with empirical data. This method uses empirically derived constitutive material models in conjunction with a traction-separation law and applicable geometry to model three-point-bending behavior of TiGr laminates. Results show that dynamic finite element simulation can accurately portray the various failure mechanisms associated with low-velocity impact. These results demonstrate a valuable tool for comparing and contrasting various TiGr layups, as well as understanding how TiGr's unique properties can be exploited to make aerospace structures stronger, lighter, and more reliable.
Book Synopsis Advanced Fatigue Damage Development in Graphite Epoxy Laminates by : Russell Douglas Jamison
Download or read book Advanced Fatigue Damage Development in Graphite Epoxy Laminates written by Russell Douglas Jamison and published by . This book was released on 1982 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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:
