Publications
119 results found
Micallef K, Fallah AS, Pope D, et al., 2013, The Dynamic Performance of Simply-Supported Rigid-Plastic Circular Thick Steel Plates Subjected to Localised Blast Loading, ASCE Journal of Engineering Mechanics, ISSN: 0733-9399
Chen A, Louca LA, Elghazouli AY, 2013, Blast response of field objects, Pages: 4545-4556
During the last few decades, several major industry accidents occurred across the world. These include the Buncefield event in the United Kingdom (UK) back in 2005. There were a number of steel switch boxes in the site located within the area covered by the vapour cloud. The present work reports numerical studies on the steel boxes covering both detonation and deflagration scenarios and assessing the response of those boxes in order to aid the investigation of the explosion. New Eulerian capabilites in ABAQUS has are together with existing Lagrangian formulations to create three numerical models with increasing complexity: (1) Pure Lagrangian model; (2) Uncoupled Eulerian - Lagrangian model; (3) Coupled Eulerian - Lagrangian model. Results from different modelling approaches are discussed and parametric studies are carried out based on Pure Lagrangian models to investigate the response of the switch box to a series of combination of pressures and impulses. Findings from the parametric study are summarised in the form of pressure - impulse diagrams and residual deformation of selected boxes are presented. The results confirmed the estiamted minimum overpressure level of 200kPa and it can also be concluded that the overpressure wave inside the cloud is most likely to be of a deflgrative form. The forensic study described in this paper has gives a good insight into the likely loading scenarios. The study presents a systematic approach for analysing the response of small objects to various blast loadings and the results have shown sthat the forensic studies can be undertaken by using the pressure - impulse diagrams in conjunction with damaged residual deformations.
Nwankwo E, Soleiman Fallah A, Langdon GS, et al., 2013, Inelastic deformation and failure of partially strengthened profiled blast walls, Engineering Structures, Vol: 46, Pages: 671-686
Mouring SE, Louca LA, Brambleby R, et al., 2012, Structural response of hybrid steel-to-composite joints
Composite materials have advanced material properties including high stiffness-and strength-toweight ratios, corrosion resistance, damage tolerance, and improved stealth characteristics. Thus, they are being used increasingly as primary structural members in military and civil applications. However due to insufficient stiffness and ductility of composites compared to traditional metallic materials, composite materials are not typically applied in isolation. This has led to an increased interest in combined metallic and composite structures. One of the major structural challenges in this area is the design of hybrid metal-to-composite joints. Hybrid joints usually entail geometry and material discontinuities that can induce stiffness mismatch and cause local stress concentrations. Current research at Imperial College London and the U.S. Naval Academy (USNA) shows that among the various types of novel metal-to-composite joints, Comeld hybrid steel-to-composite joints demonstrate significant potential in naval structural applications. These joints are fabricated using a surface treatment technique called Surfi-Sculpt, which uses a power electron beam to create metal protrusions onto which the composite is laid and cured. This paper reviews an Office of Naval Research (ONR)-sponsored research project focusing on the Comeld hybrid steel-to-composite joint design. Numerical and experimental results will be discussed and compared. This research will help provide a better understanding on how hybrid joints behave under static loading compared to conventional joints.
Micallef K, Fallah AS, Pope DJ, et al., 2012, The dynamic performance of simply-supported rigid-plastic circular steel plates subjected to localised blast loading, International Journal of Mechanical Sciences, Vol: 65, Pages: 177-191, ISSN: 0020-7403
Mouring SE, Janowski ME, Louca LA, et al., 2012, Structural performance of comeld hybrid metal-to-composite joints, Pages: 117-122, ISSN: 1098-6189
Fiber reinforced polymer (FRP) materials have advanced material properties such as high stiffness- and strength-to-weight ratios, corrosion resistance, damage tolerance, and stealth characteristics (Composites, 2002). Hence, they are being widely used as primary structural members in military and civil applications (Zhou, 2005; Shin et. al, 1997; Baker and Chester, 1993; Chalmers, 1994). However, these materials are not typically applied in isolation due to insufficient stiffness and ductility of the FRP compared to traditional metallic materials. This has led to a rapid expansion of interest in combined metal and composite structures. Design of metal-to-composite hybrid joints appears to be one of the major structural challenges. Hybrid joints usually entail geometry and material discontinuities which can induce stiffness mismatch and cause local stress concentrations. Current research at Imperial College and the U.S. Naval Academy (USNA) shows that among the various types of novel metalto- composite joints, Comeld hybrid steel-to-composite joints demonstrate significant potential in naval structural applications. These joints are fabricated using a surface treatment technique called Surfi- Sculpt which uses a power electron beam to create metal protrusions onto which the composite is laid and cured. This paper reviews the ongoing Office of Naval Research (ONR) sponsored research project focusing on the Comeld hybrid joint design. Both experimental and numerical results will be discussed and compared. These results will give needed information on how hybrid joints fail under static loading compared to conventional joints. Copyright © 2012 by the International Society of Offshore and Polar Engineers (ISOPE).
Louca LA, Mouring SE, Yang Y, et al., 2012, Frequency analysis of anisotropic 2D mechphononic metamaterials
Mechphononic metamaterials are novel materials artificially fabricated and designed to control, direct, and manipulate mechanical shock waves which would otherwise damage structural elements through propagation. Independent of its source, a shock wave's amplitude is a function of frequency in the frequency domain. Locally resonant units can be introduced into the material to stop the damaging components of the wave from propagating through a solid medium. Thus an artificial micro-structure can be designed to render the otherwise monolithic material a mechphononic metamaterial. The stiffness and inertial specifications of the introduced locally resonant units can be tailored so that a given range of frequencies is filtered out. This is equivalent to designing mechphononic metamaterials with negative effective mass density and/or stiffness, a situation similar to that of designing electromagnetic ones with negative effective inductance. The present study investigates band structure in two-dimensional (2D) anisotropic mechphononic metamaterials encompassing locally resonant mass-in-mass units buried in a massless soft matrix of a dissimilar material. The 2D lattice problem is formulated and the equations of motion are derived using Hamilton's principle. Only "resemblant anisotropy" has been considered with attenuation-free shock waves. Floquet-Bloch's principle is applied to the irreducible Brillouin zone in the k-space to extract the band structure. It was found that the phenomenon of frequency filtering exists and its extent is contingent upon the values assigned to a finite set of parameters. Dimensionless groups have been defined so that the degree and direction of influence of each parameter on the band structure can be appreciated.
Micallef K, Soleiman-Fallah A, Curtis PT, et al., 2012, A study of early-time response in dynamically loaded visco-elastic composites, Vol: 94, Pages: 1366-1378
Micallef K, Fallah AS, Pope DJ, et al., 2012, On constitutive modelling of rate-dependence in orthotropic elasto-plastic media
The aim of the present study is to develop a constitutive model which is able to capture full orthotropic behaviour of a laminated polymeric elasto-plastic composite as well as taking into account material strain-rate sensitivity, making it particularly suitable for investigation of dynamic response under high rate blast and impact loads. The formulation is an extension of the work by Ogihara and Reifsnider and including strain-rate effects using the method proposed by Thiruppukuzhi and Sun. The proposed model is implemented in incremental form as a VUMAT in ABAQUS/Explicit and a set of parametric studies assessing dependence on strain-rate and loading direction are carried out. From this study, it is found that the proposed model is suitable for characterisation of composites subjected to dynamic loads and by using appropriate values of material parameters, the model can also be used for various composite architectures, including woven and uni-directional.
Micallef K, Fallah AS, Pope DJ, et al., 2012, Mesh-insensitive finite element modelling of elastic-plastic composites
The aim of the present study is to investigate the behaviour of high-performance polypropylene based composites, such as Dyneema® and extract the response under tension, compression and shear. An energy-based approach to model the observed behaviour is presented. The proposed model is mesh-size independent by ensuring that the maximum element size does not exceed a computed value. Alternatively, the softening curve is adjusted such that the energy equivalence is maintained. A damage index is formulated to degrade material stiffness in each direction and also taking into account permanent plastic deformation under tensile loading. Compressive behaviour is accounted for by a simplified elastic-plastic response while shear deformation is characterised by a cubic stress-strain response. The proposed formulation will be implemented in a commercial finite element package, such as ABAQUS/Explicit, by means of a user-defined subroutine (VUMAT) and used to model extreme loading events on Dyneema® panels under localised and global blast loading.
Shah S, Fallah A, Louca L, 2012, On the chaotic dynamic response of deterministic nonlinear single and multi-degree-of-freedom systems, Journal of Mechanical Science and Technology, Vol: 26, Pages: 1697-1709-1697-1709, ISSN: 1738-494X
This paper presents a comprehensive study on counter-intuitive or chaotic dynamic response of prototype discrete parameter models of single or multiple degrees of freedom subject to blast or impact loading. Non-linear dynamic behaviour of a typical single degree-of-freedom (SDOF) and multi-degree-of-freedom (MDOF) systems are studied by taking into account cubic and quintic non-linearities, elastic perfect-plastic, and elastic-plastic-hardening and softening behaviours. The first part is founded on Duffing’s equation and Ueda’s work on strange attractors which indicates the presence of chaos in deterministic systems by using chaos detection techniques such as Poincare’s mapping and Lyapunov’s exponents and in some cases by fractal dimensions. In these deterministic problems, the system hesitates to settle between two different possible settling regimes despite the fact that the input parameters to the system are deterministic. In a SDOF model with elastic perfectly-plastic or elastic-plastic-hardening resistance function the sign of the permanent plastic deformation may or may not coincide with that of loading direction hence chaotic behaviour can be observed. For an elastic-plastic-softening system, subjected to blast loading, the problem is sensitive to the ratio of post yield stiffness to initial stiffness and for certain ranges of this parameter a small change can replicate into an abrupt change in response. Examples are included of finite elements models with many degrees of freedom of beams and plates. As most intricate engineering structures are composed of these structural elements the existence of component chaos can imply global counter-intuitive behaviour.
Micallef K, Soleiman-Fallah A, Curtis PT, et al., 2011, Constitutive formulation of strain-rate sensitive deformation in orthotropic composites, Pages: 397-408, ISSN: 1743-355X
The aim of the current study is to develop a constitutive model which captures the full orthotropic behaviour of a laminated composite by employing 9 material parameters and also taking into account strain-rate sensitivity to loading. The formulation is an extension of the work by Ogihara and Reifsnider (DOI: 10.1023/A:1016069220255), whose model considers 4 parameters, and with the inclusion of strain-rate effect considerations using the method employed by Thiruppukuzhi and Sun (DOI: 10.1016/S0266-3538(00)00133-0). A plastic potential function which can describe plasticity in all directions, including fibre plasticity, is chosen and using an associated flow rule, the plastic strain-rate components are derived. The plastic compliance matrix is assembled, using a rate-dependent visco-plastic modulus. The elastic compliance matrix is combined with its plastic counterpart to give a rate-form constitutive law. It is found that the proposed model accounts for strain-rate dependence and by correct choice of model parameters, the model can also be used for various composite architectures, including woven and uni-directional architectures. © 2011 WIT Press.
Fallah AS, Louca LA, 2011, Strengthening profiled blast walls and connections using fibre-reinforced plastics, P I CIVIL ENG-STR B, Vol: 164, Pages: 355-373, ISSN: 0965-0911
Louca LA, Mouring SE, Yang Y, et al., 2011, A study of wave propagation in anisotropic 2D metamaterials
Phononic metamaterials are novel artificially fabricated materials designed to control, direct, and manipulate mechanical shock waves which would otherwise, through propagation, damage the structural elements. Independent of its source, any such wave in the frequency domain possesses an amplitude which is a function of frequency. In order to stop all the damaging components whether sonic, infrasonic, or ultrasonic, propagating in a solid medium, locally resonant units are introduced in the material. These stiffness and inertial specifications of these locally resonant units can be tailored so that a given range of frequencies is filtered out and thus not able to propagate. It is possible to design phononic/acoustic metamaterials with negative effective mass density as it is to design electromagnetic ones with negative effective inductance. In the present study, anisotropic two-dimensial (2D) phononic metamaterials areinvestigated as an infinite lattice with lumped masses and discrete stiffness elements of different directional characteristics (thus the term "anisotropic"). The situation is similar to that of a locally resonant mass-in-mass unit embedded in a matrix of different material with different vertical and horizontal distances. A parametric study on the mass and stiffness ratios is conducted by applying the Floquet-Bloch's principle in conjunction with Buckingham's Pitheorem to study the band structure of such 2D lattice with different non-dimensional input parameters. The results obtained from this study provide a better understanding of the wave propagation in metamaterials. Based on this, metamaterials can be designed with the desired band structure to filter damaging high frequency components.
Fallah AS, Johnson HE, Louca LA, 2011, Experimental and numerical investigation of buckling resistance of marine composite panels, Journal of Composite Materials, Vol: 45, Pages: 907-922-907-922
The in-plane load-bearing capacity of marine composite plates is an area that has received little attention, in contrast to the significantly larger buckling and post-buckling studies available on aeronautical composites. The aim of this study is to investigate experimentally the strength to failure of large woven composite panels and correlate the results with finite element analyses. The tests performed were able to demonstrate the well-known sensitivity of the panels to boundary conditions and panel imperfection size, which is also reflected in a parametric study carried out in Abaqus/Standard. Two-dimensional stress-based failure criteria were implemented via a user-defined field (USDFLD) subroutine to detect matrix and fiber damage, which allows progressive damage to be modeled. A modification of Hashin’s failure criteria proved to be the most effective in capturing both the size and location of the damage and obtain a good approximation of the load—displacement history and surface strains.
Yang Y, Fallah AS, Saunders M, et al., 2011, On the dynamic response of sandwich panels with different core set-ups subject to global and local blast loads, Engineering Structures, Vol: 33, Pages: 2781 - 2793-2781 - 2793, ISSN: 0141-0296
The recent increase in blast and impact threats has led to an emerging interest in sandwich structures due to their superior performance in such loading environments. The optimised architecture of this class in conjunction with additional benefits of high strength-to-weight and stiffness-to-weight ratios vital to weight-sensitive military applications has led to numerous research works on the topic. In this study, the dynamic response of four circular sandwich panel constructions with different core designs under global and local blast loading conditions has been investigated. Numerical finite element (FE) models have been set up to study the effect of additional core interlayers on blast resistance enhancement of these sandwich panels. The objectives are (1) to assess the existing blast resistance capacity, (2) to increase the dynamic energy absorption, (3) to improve the stress distribution through plastic deformation, and (4) to ensure sacrificial damage to the additional core layers; hence, to avoid the main part of the core being damaged by excessive shear deformation, the dominant failure mode in conventional sandwich panels. A ductile elastomeric layer of polyurea, and a fairly compressible Divinycell-H200 foam layer have been selected as the additional core interlayers, and they have been placed in different arrangements to improve the overall blast resistance of the standard sandwich panel with glass-fibre-reinforced plastic (GFRP) face-sheets, and balsawood core. Dynamic explicit FE analyses were carried out using the commercial package ABAQUS 6.9-1. Comparison of specific kinetic and strain energies shows the effect of additional core layers on the blast energy absorption of a sandwich system. The study shows the improvement in shear failure prevention of the core as a result of the use of additional core layers and a reduction in the level of kinetic and strain energies in the protected core in both absolute and relative terms. The stress contours show a
Govender RA, Louca LA, Fallah AS, et al., 2011, Determining the through-thickness properties of thick glass fibre reinforced polymers at high strain rates, Journal of Composite Materials
The use of thick fiber reinforced polymer (FRP) laminates in composite armor and naval structures requires thorough characterization of the through-thickness properties of said laminates, both quasi-statically and at high strain rates. Specimens cut from an E-Glass/vinyl ester FRP were tested in compression both quasi-statically and dynamically using a split Hopkinson pressure bar (SHPB). The SHPB tests utilized a conical striker for pulse shaping, to reduce the variation in strain rate during the test. The quasi-static through-thickness compressive strength was 417 MPa, while the SHPB tests produced a strength of 462 MPa at an average strain rate of 5.1 × 102 s-1. A single HPB configured for spalling tests was used to determine the dynamic through-thickness tensile strength (interlaminar tension). The interlaminar tensile strength was 125 MPa at an average strain rate of 1.8 × 103 s-1.
Micallef K, Soleiman-Fallah A, Curtis PT, et al., 2011, Analytical and numerical study of early-time response in pulse-loaded visco-elastic composites, 3rd International Workshop on Performance, Protection and Strengthening of Structures Under Extreme Loading, Publisher: TRANS TECH PUBLICATIONS LTD, Pages: 214-+, ISSN: 1660-9336
Mathias S, Fallah A, Louca L, 2011, An approximate solution for toughness-dominated near-surface hydraulic fractures, International Journal of Fracture, Vol: 168, Pages: 93-100-93-100, ISSN: 0376-9429
Asymptotic solutions for fracture opening, volume and specific surface energy for small and large fracture radii are presented from the literature. By comparison to numerical simulation of static circular fractures subject to constant and uniform internal pressures, it is found that a good approximation for fracture opening, for intermediate fracture radii, is obtained from a power mean (with exponent 1/2) of the small and large fracture radii limiting cases. The power mean equation for fracture opening is used to derive corresponding equations for fracture volume, specific surface energy and mode I and II stress intensities. These are then combined to form an approximate solution to describe the propagation of circular toughness-dominated near-surface hydraulic fractures, suitable for small, large and intermediate fracture radii. The approximate solution is shown to closely approximate results from equivalent numerical simulation.
Dean J, S-Fallah A, Brown PM, et al., 2011, Energy absorption during projectile perforation of lightweight sandwich panels with metallic fibre cores, Composite Structures, Vol: 93, Pages: 1089 - 1095-1089 - 1095, ISSN: 0263-8223
This paper concerns energy absorption during projectile penetration of thin, lightweight sandwich panels with metallic fibre cores. The panels were made entirely of austenitic stainless steel (grade 304). The faceplates were 0.4 mm thick and the core (∼1–2 mm thick) was a random assembly of metallic fibres, consolidated by solid state sintering. The impact tests were simulated using ABAQUS. Faceplate behaviour was modelled using the Johnson and Cook plasticity relation and a strain rate-dependent, critical plastic strain failure criterion. The core was modelled as an anisotropic, compressible continuum, with failure based on a quadratic, shear stress-based criterion. The experimental data show that, with increasing impact velocity, the absorbed energy decreased from the ballistic limit, reached a minimum value, and then underwent a monotonic increase. The FEM modelling demonstrates that this increase arises from the kinetic energy of ejected fragments, while the energy absorbed by plastic deformation and fracture tends to a plateau. Normalised absorbed energies have been compared to values for single faceplates. The sandwich panels are marginally superior to single plates on an areal density basis.
Mouring SE, Yang Y, Louca LA, 2010, Structural response of steel-to-composite hybrid joints under tensile loading, ISSN: 0891-0138
The U.S. Navy is investigating the feasibility of hybrid combatant hulls with composites providing tailorability and reduced signature and steel providing excellent stiffness, strength, and ductility. Hybrid joints are most critical and are of major interest to the Office of Naval Research (ONR) Hybrid Composites Survivable Structures Program. This ongoing research project is in support of this ONR program. Specifically the integrity of several hybrid steel-to-composite joint details under static and dynamic loading is being examined. The research has involved collaboration with two companies involved in a STTR Phase I Option funded by ONR and supported by Naval Surface Warfare Center Carderock Division (NSWCCD). This research gives necessary information on how various hybrid joint configurations fail under both static and dynamic loading compared to conventional joints. The paper focuses specifically on several hybrid joint concepts subjected to static loading. Experimental results have been compared to results from Finite Element Analysis (FEA).
Louca LA, Fallah AS, 2010, The use of composites in blast-resistant walls, BLAST PROTECTION OF CIVIL INFRASTRUCTURES AND VEHICLES USING COMPOSITES, Editors: Uddin, Publisher: WOODHEAD PUBL LTD, Pages: 298-341
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- Citations: 4
Mouring SE, Yang Y, Louca LA, et al., 2009, Behavior of steel-to-composite hybrid joints subjected to tensile loading, ISSN: 0891-0138
The Navy is interested in hybrid combatant hulls with steel providing excellent stiffness, strength, and ductility and composites providing tailorability and reduced signature. Hybrid joints are most critical and are of great interest to the Office of Naval Research (ONR) Hybrid Composites Survivable Structures Program. This ongoing research project is in support of this ONR program. Specifically the integrity of hybrid metal-to-composite connection details under static and dynamic loading regimes is being examined. The work is part of an ONR Global NICOP project with Dr. Mouring and Dr. Louca as the U.S. and international co-principal investigators, respectively. The research has included collaboration with two companies involved in a STTR Phase I Option funded by ONR and supported by Naval Surface Warfare Center Carderock Division (NSWCCD). This research eventually will give needed information on how various hybrid joint configurations fail under both static and dynamic loading compared to conventional joints. The paper will focus specifically on one hybrid joint geometry subjected to static tensile loads. Both experimental and analytical results will be discussed.
Yang Y, Fallah AS, Louca LA, 2009, A numerical study to investigate the effect of application of a polyurea layer on energy absorption of sandwich systems
Energy absorption in a sandwich panel is the most important parameter in a blast or impact scenario. The present work investigates the effect that an elastomeric material layer of polyurea can have on this parameter. As a starting point in the present work a steel beam has been studied under pulse loading. Alterations to the frequencies of the beam when a layer of polyurea is attached are studied using a linear perturbation method. Specific kinetic and strain energy variations for the steel beam with and without polyurea have been compared when subjected to a blast load using dynamic explicit finite element analysis. Subsequently, a shock load is applied on a sandwich panel with glass fibre reinforced plastic (GFRP) faces and balsa wood core and its polyurea strengthened counterpart. Material and geometric nonlinearities are allowed and damage to the core is modelled using an anisotropic plasticity damage model along with a quadratic shear failure criterion suitable for balsa wood failure modelling. Comparison of specific kinetic and strain energies shows the effect a layer of polyurea can have on blast energy absorption of a sandwich system along with the limitations of its utilisation. The study shows the improvement in shear failure prevention of the core as a result of use of a layer of polyurea and a reduction in the level of kinetic and strain energies in the core.
Yang Y, Fallah AS, Louca LA, 2009, Frequency analysis of a heterogeneous perforated panel using a super-element formulation, Journal of Sound and Vibration, Vol: 327, Pages: 26 - 40-26 - 40, ISSN: 0022-460X
Heterogeneous perforated panels represent a wide class of structural elements with holes where perforations and matrix are of dissimilar materials e.g. metallic member of a perforated hybrid joint with resin-fillings. There is a variety of objectives for introducing holes e.g. weight saving or mechanical interlock. Where there is a regular pattern to the arrangement of holes the perforated element can be assimilated to a lattice. In the present study, numerical analysis has been conducted on investigating the shock frequency filtering phenomenon encountered in two-dimensional (2D) lattice structures. A super-element of the primitive cell (unit cell) of the lattice has been formulated and applied in conjunction with the Floquet–Bloch’s principle to study the shock response characteristics. Plane wave propagation is investigated by constructing the first Brillouin zone of the primitive cell in associated Fourier space (k-space). The frequency characteristics are presented in the band structure diagram. The study emphasizes the existence of frequency pass and stop bands and the extent of this phenomenon. The frequency filtering effects of the heterogeneous perforated 2D lattice has shown its potential value to improve the structural performance of perforated hybrid joints subjected to dynamic loads.
Johnson HE, Louca LA, Mouring S, et al., 2009, Modelling impact damage in marine composite panels, International Journal of Impact Engineering, Vol: 36, Pages: 25 - 39-25 - 39, ISSN: 0734-743X
In order to establish the survivability of a composite structure under a dynamic load, it is important to be able to predict the damage incurred and the effect of the contact force. The damage caused by low velocity impact is often hidden and for thicker plates the transverse stresses are significant in promoting delamination. In this study, woven vinyl-ester composite plates up to 1.37 m long are numerically modelled with a simple, gradually damaging three-dimensional material model and the results are compared with full-scale tests. The model is based on damage mechanics principles using cyclic test data to obtain modulus reduction with damage. Delamination is modelled with a mixed-mode traction-separation law using cohesive elements. The nonlinear elastic orthotropic material model for the woven plies is written in a VUMAT in Abaqus/Explicit and the effects of varying some of the modelling parameters are briefly discussed through the examination of the contact force.
Fallah AS, Johnson HE, Louca LA, et al., 2008, Numerical simulation of impact induced damage in marine composite panels, ISSN: 0891-0138
In order to establish the survivability of a composite panel in an impact scenario it is important to be able to predict the damage incurred and the effect of the contact force. The damage caused by low velocity impact is barely visible and a hidden menace and for thick plates transverse stresses are significant in promoting delamination. In the present work woven vinyl-ester composite plates up to 1.37m long are numerically modelled with a simple, gradually damaging three dimensional material model and the results are compared with full-scale tests. The model is based on damage mechanics principles using cyclic test data to obtain modulus reduction with damage. Delamination is modeled with a mixed-mode traction-separation law using cohesive elements. The non-linear elastic orthotropic material model for the woven plies is written in a VUMAT subroutine in Abaqus/Explicit and the effects of varying some of the modelling parameters are briefly discussed through the examination of the contact force.
Zhou DW, Louca LA, Saunders M, 2008, Numerical simulation of sandwich T-joints under dynamic loading, COMPOSITES PART B-ENGINEERING, Vol: 39, Pages: 973-985, ISSN: 1359-8368
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- Citations: 32
Ali RMM, Louca LA, 2008, Performance-based design of blast resistant offshore topsides, Part II: Modelling and design, JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH, Vol: 64, Pages: 1046-1058, ISSN: 0143-974X
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- Citations: 8
Ali RMM, Louca LA, 2008, Performance based design of blast resistant offshore topsides, Part I: Philosophy, JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH, Vol: 64, Pages: 1030-1045, ISSN: 0143-974X
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- Citations: 7
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