The Experts below are selected from a list of 623550 Experts worldwide ranked by ideXlab platform
Wesley J. Cantwell - One of the best experts on this subject based on the ideXlab platform.
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the low velocity Impact Response of foam based sandwich panels
Composites Science and Technology, 2012Co-Authors: Jin Zhou, Mohamad Zaki Hassan, Zhongwei Guan, Wesley J. CantwellAbstract:Abstract This paper describes the results of a combined experimental/numerical study to investigate the perforation resistance of sandwich structures. The Impact Response of plain foam samples and their associated sandwich panels was characterised by determining the energy required to perforate the panels. The dynamic Response of the panels was predicted using the finite element analysis package ABAQUS/Explicit. The experimental arrangement, as well as the FE model were also used to investigate, for the first time, the effect of oblique loading on sandwich structures and also to study the Impact Response of sandwich panels on an aqueous support. Testing has shown that the perforation resistance of the plain foams and their sandwich panels is strongly dependent on the properties of the foam core. For example, increasing the density of the crosslinked PVC foams from 60 to 200 kg/m 3 yielded an eight fold increase in the perforation resistance of the sandwich panels. At intermediate and higher densities, the crosslinked PVC foams and their associated sandwich structures offered a superior perforation resistance to their linear PVC counterparts. The FE analysis reasonably predicted the Impact load–displacement Responses and the perforation energies of both the plain foams and the sandwich panels. Finally, it has been shown that sandwich panels Impacted in an aqueous environment offer a lower perforation resistance than those tested in air.
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low velocity Impact Response of high performance aluminum foam sandwich structures
Journal of Reinforced Plastics and Composites, 2005Co-Authors: H Kiratisaevee, Wesley J. CantwellAbstract:The Impact Response of a range of novel sandwich structures based on fiber-reinforced thermoplastic and fiber-metal laminate (FML) skins is studied. Indentation tests on these structures show that the indentation constants in a generalized indentation law exhibit a rate-sensitive Response over the range of loading conditions examined here. Low-velocity Impact tests show that these systems are capable of absorbing energy through localized plastic deformation and crushing in the metal core. An energy-balance model accounting for energy dissipation in bending, shear, and indentation effects is used to predict the maximum force during the Impact event. It is found that the model accurately predicts the low-velocity Impact Response of the plain sandwich structures up to energies close to 30 J. In contrast, the model is only capable of predicting the low-energy Response of the FML sandwich structures (typically up to 2 J). At higher energies, a horizontal shear crack initiates in the metal core causing the maximum force to drop below that predicted by the model. Using an energy-partitioning approach, it is shown that indentation effects account for over half of the energy absorbed in the FML-based sandwich structures.
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the high velocity Impact Response of composite and fml reinforced sandwich structures
Composites Science and Technology, 2004Co-Authors: Reyes G Villanueva, Wesley J. CantwellAbstract:The high velocity Impact Response of a range of novel aluminium foam sandwich structures has been investigated using a nitrogen gas gun. Tests were undertaken on sandwich structures based on plain composite and fibre-metal laminate (FML) skins. Impact testing was conducted using a 10 mm diameter projectile at energies up to that required to achieve complete perforation of the target. High velocity Impact tests on the sandwich structures resulted in a number of different failure modes. Delamination and longitudinal splitting of the composite skins were observed in the unidirectional glass fibre/polypropylene-based systems. In contrast, the woven glass fibre/polypropylene-based sandwich structures exhibited smaller amounts of delamination after high velocity Impact testing. In addition, the aluminium foam in both systems exhibited a localised indentation failure followed by progressive collapse at higher Impact energies. The ballistic limit of all of the sandwich structures was predicted using a simple analytical model. It has been shown that the predictions of the model are in good agreement with the experimental data. Finally, it has been shown that these novel systems offer excellent energy absorbing characteristics under high velocity Impact loading conditions.
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The low velocity Impact Response of an aluminium honeycomb sandwich structure
Composites Part B-engineering, 2003Co-Authors: Akil Hazizan, Wesley J. CantwellAbstract:Abstract The low velocity Impact Response of two aluminium honeycomb sandwich structures has been investigated by conducting drop-weight Impact tests using an instrumented falling-weight Impact tower. Initially, the rate-sensitivity of the glass fibre reinforced/epoxy skins and aluminium core was investigated through a series of flexure, shear and indentation tests. Here, it was found that the flexural modulus of the composite skins and the shear modulus of the aluminium honeycomb core did not exhibit any strain-rate sensitivity over the conditions investigated here. In addition, it was found that the indentation characteristics of this lightweight sandwich structure can be analysed using a Meyer indentation law, the parameters of which did not exhibit any sensitivity to crosshead displacement rate. The Impact Response of the aluminium honeycomb sandwich structures was modelled using a simple energy-balance model which accounts for energy absorption in bending, shear and contact effects. Agreement between the energy-balance model and the experimental data was found to be good, particularly at low energies where damage was localised to the core material immediate to the point of Impact. The energy balance was also used to identify energy partitioning during the Impact event. Here, it was shown that the partition of the incident energy depends strongly on the geometry of the Impacting projectile.
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The low velocity Impact Response of foam-based sandwich structures
Composites Part B-engineering, 2002Co-Authors: Akil Hazizan, Wesley J. CantwellAbstract:Abstract The low velocity Impact Response of a range of foam-based sandwich structures has been investigated using an instrumented falling-weight Impact tower. Initially, the rate-sensitivity of the skin and core materials was investigated through a series of flexure and indentation tests. Here, it was shown that the flexural modulus of the skins and all 11 foam materials did not exhibit any sensitivity to crosshead displacement rate over the conditions studied here. In addition, it was shown that the indentation Response of the sandwich structures could be modelled using a simple indentation law, the parameters of which did not exhibit any sensitivity to loading rate. Low velocity Impact tests on the sandwich structures resulted in a number of different failure modes. Here, shear fracture was found to occur in the PVC/PUR systems based on brittle core materials. In contrast, buckling failures in the uppermost composite skin were observed in the intermediate modulus systems, whereas initial damage in the higher modulus PVC/PUR systems took the form of delamination within the top surface skin. It has been shown that a simple energy-balance model based on the dissipation of energy during the Impact event can be used to successfully model the elastic Response of foam-based sandwich structures. The energy-balance model is particularly useful since it can be used to establish the partition of energy during the Impact process.
Qinghua Qin - One of the best experts on this subject based on the ideXlab platform.
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low velocity Impact Response of fully clamped metal foam core sandwich beam incorporating local denting effect
Composite Structures, 2013Co-Authors: Qinghua QinAbstract:Local denting caused by low-velocity heavy mass Impact is one of the active failure mechanisms of sandwich structures, which is important for the structural integrity assessment of sandwich structures. The objective of this work is to investigate the low-velocity Impact Response of metal foam core sandwich beams incorporating local denting effect. Analytical and numerical solutions are obtained for the structural Response of fully clamped sandwich beams struck by a heavy mass with low velocity. The effects of local denting and foam core strength on the overall deformation of the sandwich beams are considered in theoretical analysis. Comparisons of the analytical and numerical results are presented and good agreement is achieved between the predictions and numerical results. It is seen that the load-carrying capacity of sandwich structures may be overestimated if the effect of local denting is neglected in theoretical analysis.
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low velocity heavy mass Impact Response of slender metal foam core sandwich beam
Composite Structures, 2011Co-Authors: Qinghua Qin, T J WangAbstract:Abstract The objective of this work is to investigate the dynamic large deflection Response of fully clamped metal foam core sandwich beam struck by a low-velocity heavy mass. Analytical solution and ‘bounds’ of dynamic solutions are derived, respectively. Also, finite element analysis is carried out to obtain the numerical solution of the problem. Comparisons of the dynamic, the quasi-static and numerical solutions for the non-dimensional maximum deflection of the sandwich beam with non-dimensional initial kinetic energy of the striker are presented for different cases of mass ratio, Impact velocity and location. It is seen that the dynamic solution approaches the quasi-static one as the mass ratio of the striker to the beam is large enough, the quasi-static solution is in good agreement with the numerical results and both solutions lie in the ‘bounds’ of dynamic solutions. The quasi-static and numerical results for the Impact force against the maximum deflection of the sandwich beam are obtained. It shows that the quasi-static solution can offer adequate accuracy to predict the low-velocity heavy-mass Impact Response of fully clamped sandwich beam.
Cesim Atas - One of the best experts on this subject based on the ideXlab platform.
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the effect of face sheet thickness on low velocity Impact Response of sandwich composites with foam cores
Journal of Sandwich Structures and Materials, 2016Co-Authors: Cesim Atas, Umut PotogluAbstract:This paper presents an experimental investigation on Impact Response of sandwich composite panels with different face-sheet thicknesses. A number of low velocity Impact tests were performed under various Impact energies. The damage process of the sandwich composites consisted of glass/epoxy face-sheets, and foam cores are analyzed from cross-examining some graphs such as load–deflection curves and damaged specimens. The primary damage modes observed are fiber fractures at upper and lower skins, delaminations between adjacent glass-epoxy layers, and core shear fractures.
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thickness effect on repeated Impact Response of woven fabric composite plates
Composites Part B-engineering, 2013Co-Authors: Cesim Atas, Ulent Mura Icte, Mumi KucukAbstract:Abstract This paper presents an experimental investigation on the repeated Impact Response of woven E-glass/epoxy composites with various thicknesses. Energy profile diagrams of the samples, the variation of perforation thresholds with thickness and the variation of absorbed energy with repeat numbers are provided. Considering varied energy levels, the Impact numbers causing complete perforation of the specimens are also depicted. Along with some images of the perforated samples for both single Impact and repeated Impact cases, the contour plots of the damage expansion with increasing Impact numbers are also provided for better understanding. It is found that the perforation threshold/energy for single Impact varies linearly with thickness for the chosen composite plates. Considering different energy levels, the Impact numbers corresponding complete perforation of the specimens with different thicknesses, i.e. layer numbers, are also provided. It is found that the data points of the each thickness, using power regression, may be written as; E i = aN r b , where E i stands for Impact energy, N r for the “repeat number of Impact to perforation”, while a and b are the constants. The equations found enable to predict the number of Impacts for perforation ( N r ) under smaller Impact energies, without testing.
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on the Impact Response of sandwich composites with cores of balsa wood and pvc foam
Composite Structures, 2010Co-Authors: Cesim Atas, Cenk SevimAbstract:Abstract This paper presents an experimental investigation on Impact Response of sandwich composite panels with PVC foam core and balsa wood core. A number of tests were performed under various Impact energies. Damage process of the sandwich composites is analyzed from cross-examining load–deflection curves, energy profile diagrams and the damaged specimens. The primary damage modes observed are; fiber fractures at upper and lower skins, delaminations between adjacent glass–epoxy layers, core shear fractures, and face/core debonding. After visual inspection of the top and bottom face-sheets, initial examination, damage mechanisms at the interior layers and cores were ascertained through destructive analysis, i.e. sectioning by an abrasive water-jet machine, of samples. In addition to the single Impacts, repeated Impact Response of the samples is also investigated.
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low temperature effect on Impact Response of quasi isotropic glass epoxy laminated plates
Composite Structures, 2009Co-Authors: Bulent Murat Icten, Cesim Atas, Mehmet Aktas, Ramazan KarakuzuAbstract:Abstract In this study, the Impact behavior of laminated glass–epoxy composites at several temperatures (20 °C, −20 °C and −60 °C) was studied experimentally. Impact tests were performed by using Fractovis Plus Impact test machine with a constant Impactor mass of 5.02 kg. Composite specimens with stacking sequence [0/90/45/−45]S were Impacted at varied Impact energies ranging from 5 J to 70 J. Variation of the Impact characteristics such as maximum contact load, maximum deflection, maximum contact time and absorbed energy versus Impact energy are depicted in figures. Results indicated that the ambient temperature highly affects the Impact Response of composite materials.
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an experimental investigation of the Impact Response of composite laminates
Composite Structures, 2009Co-Authors: Mehmet Aktas, Cesim Atas, Bulent Murat Icten, Ramazan KarakuzuAbstract:Abstract In this study, the Impact Response of unidirectional glass/epoxy laminates has been investigated by considering energy profile diagrams and associated load–deflection curves. Damage modes and the damage process of laminates under varied Impact energies are discussed. Two different stacking sequences, [0/90/0/90] s and [0/90/+45/−45] s , were chosen in tests for comparison. An alternative method, based on variation of the excessive energy ( E e ) versus Impact energy ( E i ), is presented to determine penetration threshold (Pn). The penetration threshold for stacking sequence [0/90/+45/−45] s is found to be smaller than that of [0/90/0/90] s . The primary damage mode was found to be fiber fracture for higher Impact energies; whereas, it was indentation resulting in delamination and matrix cracks for smaller Impact energies. Contour plots of the overall damage areas are also depicted for several Impact energies.
Stephen W Rouhana - One of the best experts on this subject based on the ideXlab platform.
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abdominal Impact Response to rigid bar seatbelt and airbag loading
Stapp car crash journal, 2001Co-Authors: Warren N Hardy, Lawrence W. Schneider, Stephen W RouhanaAbstract:The objective of this study was to resolve discrepancies and fill in some of the gaps in the biomechanical Impact Response of the human abdomen to frontal Impact loading. Three types of abdominal loading were described: rigid-bar Impacts; seatbelt loading; and close-proximity (out-of-position) airbag deployments. This describes how eleven rigid-bar free-back tests were performed into the mid and upper abdomens of unembalmed instrumented human cadavers using nominal Impact speeds of 6 and 9 m/s. Seven fixed-back rigid-bar testes were also conducted in 3, 6, and 9 m/s using one cadaver to examine the effects of body mass, spinal flexion, and repeated testing. It describes how load-penetration corridors were developed and compared to those previously established by other researchers. Six seatbelt tests were conducted using three cadavers and a peak-loading rate of 3 m/s. The seatbelt loading tests were designed to maximize belt/abdomen interaction and were not necessarily representative of real-world crashes. The results were compared to previously obtained data using swine and they were used to establish a new abdominal load-penetration corridor belt loading. Passenger frontal airbags were deployed into the closely positioned abdomen of three unembalmed cadavers. The penetration-time histories were used to guide the development of a repeatable high-speed surrogate airbag-loading device that uses a low-mass cylinder to stimulate the initial breakout phase of close-proximity passenger airbag loading of the abdomen. The device was used to conduct simulated out-of-position airbag tests into three cadaver abdomens. The abdomen Response data from these standardized tests were used to develop a load-penetration corridor for abdomen Response to out-of-position airbag deployments.
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abdominal Impact Response to rigid bar seatbelt and airbag loading
Stapp car crash journal, 2001Co-Authors: Warren N Hardy, Lawrence W. Schneider, Stephen W RouhanaAbstract:This study was conducted to resolve discrepancies and fill in gaps in the biomechanical Impact Response of the human abdomen to frontal Impact loading. Three types of abdominal loading were studied: rigid-bar Impacts, seatbelt loading, and close-proximity (out-of-position) airbag deployments. Eleven rigid-bar free-back tests were performed into the mid and upper abdomens of unembalmed instrumented human cadavers using nominal Impact speeds of 6 and 9 m/s. Seven fixed-back rigid-bar tests were also conducted at 3, 6, and 9 m/s using one cadaver to examine the effects of body mass, spinal flexion, and repeated testing. Load-penetration corridors were developed and compared to those previously established by other researchers. Six seatbelt tests were conducted using three cadavers and a peak-loading rate of 3 m/s. The seatbelt loading tests were designed to maximize belt/abdomen interaction and were not necessarily representative of real-world crashes. The results were compared to data previously obtained by other researchers using swine and were used to establish a new abdominal load-penetration corridor for belt loading. Passenger frontal airbags were deployed into the closely positioned abdomen of three unembalmed cadavers. The penetration-time histories were used to guide the development of a repeatable high-speed surrogate airbag-loading device that uses a low-mass cylinder to simulate the initial breakout phase of close-proximity passenger airbag loading of the abdomen. This device was used to conduct simulated out-of-position airbag tests into three cadaver abdomens. The abdomen Response data from these standardized tests were used to develop a load-penetration corridor for abdomen Response to out-of-position airbag deployments.
Onur Sayman - One of the best experts on this subject based on the ideXlab platform.
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comparative study on repeated Impact Response of e glass fiber reinforced polypropylene epoxy matrix composites
Composites Part B-engineering, 2015Co-Authors: Volkan Arikan, Onur SaymanAbstract:Abstract In this study, E-glass fiber reinforced composites have been manufactured with two types of resin, polypropylene and epoxy (Thermoplastic and Thermoset) and they have been subjected to the low velocity single and repeated Impacts and effect of resin type on the Impact Response of composites are investigated. Impact energies were chosen as 20 J, 50 J, 80 J and 110 J for single Impact tests while 50 J was chosen for repeated Impact tests. Comparisons between the results of 110 J single and 50 J repeated Impacted specimens were performed. As a result of the study it is concluded that the resin type is a crucial parameter for the repeated Impact Response of the composites.
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an overall view on Impact Response of woven fabric composite plates
Composite Structures, 2008Co-Authors: Cesim Atas, Onur SaymanAbstract:Abstract This paper presents an overall view on Impact Response of woven fabric composite plates made of E-glass as reinforcing material and epoxy resin as matrix material. A number of tests were performed under various incident Impact energies ranging from approximately 4–45 J. Hence, it was possible to examine the damage process step by step from initiation of damage to final perforation. It is shown that the damage process of individual specimens can be reconstructed from comparing the corresponding load–deflection curves, energy profile diagram and images of damaged specimens. In addition to the load–deflection curves, variation of other Impact parameters such as absorbed energy and velocity versus deflection or time are depicted. The correlation between those Impact parameters and damage process is also constructed.
