Publications
177 results found
Pascoe J-A, Pimenta S, Pinho S, 2020, Example analysis input files for CZM analysis of delamination growth in a DCB specimens
The files in this collection accompany the paper 'How to set up a cohesive zone model for an LEFM dominated problem: a detailed analysis for first time users', submitted to Applied Mechanics Reviews. The files comprise input files that allow reproduction of the example analyses shown in that paper. The purpose of the paper is to show how to determine appropriate values of various numerical parameters required when setting up a cohesive zone model analysis of an LEFM dominated crack propagation problem. These parameters can be determined by running a series of convergence studies. The input files for those convergence studies as well as the final prediction are included in this collection.The example analyses for the paper were run using Abaqus/Standard 6.14, and the included files will work for that software version.
Pascoe JA, Pimenta S, Pinho ST, 2020, Interlocking thin-ply reinforcements for the improvement of CAI strength
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. A new reinforcement concept for improving compression after impact strength of carbon fibre reinforced polymers is explored. The concept consists of manufacturing interlocked reinforcement units from thin-ply prepreg, which are inserted at the interlaminar interfaces within a regular ply-thickness laminate. Compression after impact tests following ASTM standards were performed on both reinforced and baseline specimens. The reinforced specimens showed a 11.4 % reduction in post-impact delamination area. The strength results will be presented at the conference.
Schuffenhauer K, Nothdurfter SK, Li Y, et al., 2020, Virtual design of car components manufactured with high-performance discontinuous composites
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. High Performance Discontinuous Composites (HPDCs) combine performance and manufacturability, which makes them suitable for automotive structures. However, due to the intrinsic variability in the microstructure of HPDCs, the local modulus and strength of these materials are highly heterogeneous, which raises a challenge in designing and simulating the structural response of a HPDC component. This work analyses the mechanical response of the engine bonnet of the Lamborghini Huracan PERFORMANTE, simulated using a FE Monte-Carlo framework developed specifically for HPDC structures. A significant spread of the maximum failure index and location of the critical region of the bonnet is observed, which highlights the effect of variability in HPDC materials on their structural performance.
Martulli LM, Alves M, Pimenta S, et al., 2020, Predictions of carbon fibre sheet moulding compound (CF-SMC) mechanical properties based on local fibre orientation
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. Carbon Fibre-Sheet Moulding Compound materials (CF-SMC) are an innovative class of intermediate materials made of chopped carbon fibre strands dispersed in uncured (or partially cured) thermoset resin. These sheets are then compression moulded into the final desired shape. Currently, the more commonly used models for SMC mechanical properties were initially developed for injection moulded composites, where the reinforcement is in the form of individual fibres, rather than tows or bundles. However, the presence of an additional intermediate scale of inclusions in the SMCs is not considered by those models. Their accuracy is thus questionable, and their adoption challenging: the user should generally choose whether to consider inclusions as tows or fibres, and thus have access to different material parameters, not always available (for example, the volume fraction of the tows in the composite). This work aims to validate two different formulations of a mixed Mori-Tanaka iso-strain model: one where inclusions are considered to be fibres, one where inclusions are tows; in addition, stiffness predictions are compared with the ones obtained a shear-lag multiscale model, that involves description of both tows and fibres. The models are compared with experimental evidence.
Henry J, Pimenta S, 2020, Bio-inspired non-self-similar hierarchical composites
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. The use of hierarchies in naturally occurring composites motivated several studies in the literature, which demonstrated that hierarchical features could be integrated in composites to achieve damage tolerance. However, while most natural composites exhibit non-self-similarity in their hierarchical microstructure, most synthetic hierarchical designs in the literature use self-similar features. The aim of this work is therefore to investigate whether non-self-similar composites could be more damage tolerant than their self-similar equivalent. Hierarchical composites were designed, manufactured and tested, and results show that releasing the self-similar constraint could increase the design space and achieve better damage tolerance and warning before failure, and provide a more stable failure mechanism.
Finley JM, Henry J, Pimenta S, et al., 2020, The influence of defects and variability in discontinuous composite materials
A virtual testing framework was further developed to investigate the influence of defects and variability on the structural performance of various aligned discontinuous composite material systems. The virtual testing framework identified the most critical sources of variability as (i) fibre strength, (ii) the distance between fibre ends, or (iii) the level of fibre-type intermingling, depending on the material system. Fibre vacancy defects were shown to also have a significant influence on the strength and ductility of aligned discontinuous composites.
Deng X, Kinloch AJ, Pimenta S, et al., 2020, Toughening epoxy composites using nano- And microcellulose modifiers
The fracture properties and toughening mechanisms of cellulose- and cellulose-rubber hybrid-modified epoxy polymers and glass-fibre (GF) composites are investigated. The cellulose modifiers used are microcrystalline cellulose (MCC) and cellulose nanocrystals (CNC), and the rubber modifiers are carboxyl-terminated butadiene-acrylonitrile (CTBN) and core-shell rubber (CSR). The toughening mechanisms of the MCC-epoxy and CNC-epoxy were identified to be crack deflection, shear band yielding, particle rupture or pull-out and debonding of the cellulose particles, which was followed by plastic void growth. An additive toughening effect is observed for the hybrid polymers. Analytical modelling of the fracture energies showed that the particle pull-out toughening contribution is negligible for CNC-epoxy, and the particle debonding and rupture toughening contributions are negligible for MCC-epoxy. The GF composites were manufactured using the wet-layup process. Cellulose modifiers did not increase the composite propagation fracture energy (GC,prop) but slight increases in GC,prop occurred for the CNC hybrids. Increases in the fibre-matrix adhesion reduced the fibre toughening mechanisms in the composites that were modified with only MCC or CNC. The crack tip deformation zone is smaller than the MCC particles, reducing their toughening ability in the GF composites.
Pascoe JA, Pimenta S, Pinho ST, 2020, Interlocking thin-ply reinforcements for the improvement of CAI strength
A new reinforcement concept for improving compression after impact strength of carbon fibre reinforced polymers is explored. The concept consists of manufacturing interlocked reinforcement units from thin-ply prepreg, which are inserted at the interlaminar interfaces within a regular ply-thickness laminate. Compression after impact tests following ASTM standards were performed on both reinforced and baseline specimens. The reinforced specimens showed a 11.4 % reduction in post-impact delamination area. The strength results will be presented at the conference.
Li Y, Pimenta S, 2020, Development of a FE design framework to predict the response of discontinuous composite structures with heterogeneous microstructures
Tow-based discontinuous composites (TBDCs) are a growing class of high performance discontinuous composites used in structural applications. These materials have significant spatial variability in their microstructure and mechanical properties, which adds complexity to structural design using TBDCs. This study proposes a FE Monte-Carlo simulation framework to predict the mechanical response of a TBDC structure, while accounting for the variability in the microstructure of TBDCs. The simulation framework calculates a stochastic distribution of the modulus and strength of TBDCs; it then defines a characteristic spacing between uncorrelated material property points, at which the stochastic distributions of modulus and strength are assigned to a structure. The structure is then analysed in a Finite Element (FE) software, whose results are mesh-independent.
Henry J, Pimenta S, 2020, Bio-inspired non-self-similar hierarchical composites
The use of hierarchies in naturally occurring composites motivated several studies in the literature, which demonstrated that hierarchical features could be integrated in composites to achieve damage tolerance. However, while most natural composites exhibit non-self-similarity in their hierarchical microstructure, most synthetic hierarchical designs in the literature use self-similar features. The aim of this work is therefore to investigate whether non-self-similar composites could be more damage tolerant than their self-similar equivalent. Hierarchical composites were designed, manufactured and tested, and results show that releasing the self-similar constraint could increase the design space and achieve better damage tolerance and warning before failure, and provide a more stable failure mechanism.
Pimenta S, Li Y, Alves M, et al., 2020, Quantifying and predicting the effect of heterogenenous microstructures on the performance of discontinuous composites
The heterogeneous microstructure of high performance Tow-Based Discontinuous Composites (TBDCs) leads to non-uniform stochastic fields of local mechanical properties; consequently, TBDC structures present a non-deterministic response, and may fail at locations that can only be predicted with stochastic methods. We have quantified the effect of the heterogeneous microstructure on the strength of unnotched and notched tensile specimens, using a range of hole sizes; we have then used an in-house developed FE Monte-Carlo framework to predict stochastic strain fields, critical locations, and critical loads in the specimens. The results from the FE Monte-Carlo analysis provide a good qualitative agreement with the experimental data, suggesting that our framework can be used for structural design of TBDC structures.
Schuffenhauer K, Nothdurfter SK, Li Y, et al., 2020, Virtual design of car components manufactured with high-performance discontinuous composites
High Performance Discontinuous Composites (HPDCs) combine performance and manufacturability, which makes them suitable for automotive structures. However, due to the intrinsic variability in the microstructure of HPDCs, the local modulus and strength of these materials are highly heterogeneous, which raises a challenge in designing and simulating the structural response of a HPDC component. This work analyses the mechanical response of the engine bonnet of the Lamborghini Huracan PERFORMANTE, simulated using a FE Monte-Carlo framework developed specifically for HPDC structures. A significant spread of the maximum failure index and location of the critical region of the bonnet is observed, which highlights the effect of variability in HPDC materials on their structural performance.
Alves M, Pimenta S, 2020, Analysing the effect of fibre waviness on the stiffness of tow-based discontinuous composites
Tow-based discontinuous composites (TDBCs) are a particular type of discontinuous composites and are becoming a growing class in high-performance materials. These materials consist of carbon-fibre tows dispersed in a polymeric matrix, resulting in a microstructure that has an inherent 3D nature, with the tows presenting waved configurations. This work aims to develop a microstructure generator able to recreate the characteristic features of the microstructure of TBDCs, such as tow waviness and local thickness and fibre content variations; in addition, flexibility in terms of in-plane tow orientations is also considered, as the distributions of the latter are defined by orientation tensors. The microstructure generator is able to recreate representative cross-sections of these materials, and also out-of-plane angle distributions, for any type of in-plane tow orientations considered. Furthermore, the effect of the tow waviness on the stiffness of these materials is assessed, and a parametric study on the effect of the tow geometry on the in-plane stiffness reduction is carried out.
Martulli LM, Alves M, Pimenta S, et al., 2020, Predictions of carbon fibre sheet moulding compound (CF-SMC) mechanical properties based on local fibre orientation
Carbon Fibre-Sheet Moulding Compound materials (CF-SMC) are an innovative class of intermediate materials made of chopped carbon fibre strands dispersed in uncured (or partially cured) thermoset resin. These sheets are then compression moulded into the final desired shape. Currently, the more commonly used models for SMC mechanical properties were initially developed for injection moulded composites, where the reinforcement is in the form of individual fibres, rather than tows or bundles. However, the presence of an additional intermediate scale of inclusions in the SMCs is not considered by those models. Their accuracy is thus questionable, and their adoption challenging: the user should generally choose whether to consider inclusions as tows or fibres, and thus have access to different material parameters, not always available (for example, the volume fraction of the tows in the composite). This work aims to validate two different formulations of a mixed Mori-Tanaka iso-strain model: one where inclusions are considered to be fibres, one where inclusions are tows; in addition, stiffness predictions are compared with the ones obtained a shear-lag multiscale model, that involves description of both tows and fibres. The models are compared with experimental evidence.
Schuffenhauer K, Nothdurfter SK, Li Y, et al., 2020, Virtual design of car components manufactured with high-performance discontinuous composites
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. High Performance Discontinuous Composites (HPDCs) combine performance and manufacturability, which makes them suitable for automotive structures. However, due to the intrinsic variability in the microstructure of HPDCs, the local modulus and strength of these materials are highly heterogeneous, which raises a challenge in designing and simulating the structural response of a HPDC component. This work analyses the mechanical response of the engine bonnet of the Lamborghini Huracan PERFORMANTE, simulated using a FE Monte-Carlo framework developed specifically for HPDC structures. A significant spread of the maximum failure index and location of the critical region of the bonnet is observed, which highlights the effect of variability in HPDC materials on their structural performance.
Martulli LM, Alves M, Pimenta S, et al., 2020, Predictions of carbon fibre sheet moulding compound (CF-SMC) mechanical properties based on local fibre orientation
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. Carbon Fibre-Sheet Moulding Compound materials (CF-SMC) are an innovative class of intermediate materials made of chopped carbon fibre strands dispersed in uncured (or partially cured) thermoset resin. These sheets are then compression moulded into the final desired shape. Currently, the more commonly used models for SMC mechanical properties were initially developed for injection moulded composites, where the reinforcement is in the form of individual fibres, rather than tows or bundles. However, the presence of an additional intermediate scale of inclusions in the SMCs is not considered by those models. Their accuracy is thus questionable, and their adoption challenging: the user should generally choose whether to consider inclusions as tows or fibres, and thus have access to different material parameters, not always available (for example, the volume fraction of the tows in the composite). This work aims to validate two different formulations of a mixed Mori-Tanaka iso-strain model: one where inclusions are considered to be fibres, one where inclusions are tows; in addition, stiffness predictions are compared with the ones obtained a shear-lag multiscale model, that involves description of both tows and fibres. The models are compared with experimental evidence.
Pascoe JA, Pimenta S, Pinho ST, 2020, Interlocking thin-ply reinforcements for the improvement of CAI strength
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. A new reinforcement concept for improving compression after impact strength of carbon fibre reinforced polymers is explored. The concept consists of manufacturing interlocked reinforcement units from thin-ply prepreg, which are inserted at the interlaminar interfaces within a regular ply-thickness laminate. Compression after impact tests following ASTM standards were performed on both reinforced and baseline specimens. The reinforced specimens showed a 11.4 % reduction in post-impact delamination area. The strength results will be presented at the conference.
Finley JM, Henry J, Pimenta S, et al., 2020, The influence of defects and variability in discontinuous composite materials
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. A virtual testing framework was further developed to investigate the influence of defects and variability on the structural performance of various aligned discontinuous composite material systems. The virtual testing framework identified the most critical sources of variability as (i) fibre strength, (ii) the distance between fibre ends, or (iii) the level of fibre-type intermingling, depending on the material system. Fibre vacancy defects were shown to also have a significant influence on the strength and ductility of aligned discontinuous composites.
Li Y, Pimenta S, 2020, Development of a FE design framework to predict the response of discontinuous composite structures with heterogeneous microstructures
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. Tow-based discontinuous composites (TBDCs) are a growing class of high performance discontinuous composites used in structural applications. These materials have significant spatial variability in their microstructure and mechanical properties, which adds complexity to structural design using TBDCs. This study proposes a FE Monte-Carlo simulation framework to predict the mechanical response of a TBDC structure, while accounting for the variability in the microstructure of TBDCs. The simulation framework calculates a stochastic distribution of the modulus and strength of TBDCs; it then defines a characteristic spacing between uncorrelated material property points, at which the stochastic distributions of modulus and strength are assigned to a structure. The structure is then analysed in a Finite Element (FE) software, whose results are mesh-independent.
Pimenta S, Li Y, Alves M, et al., 2020, Quantifying and predicting the effect of heterogenenous microstructures on the performance of discontinuous composites
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. The heterogeneous microstructure of high performance Tow-Based Discontinuous Composites (TBDCs) leads to non-uniform stochastic fields of local mechanical properties; consequently, TBDC structures present a non-deterministic response, and may fail at locations that can only be predicted with stochastic methods. We have quantified the effect of the heterogeneous microstructure on the strength of unnotched and notched tensile specimens, using a range of hole sizes; we have then used an in-house developed FE Monte-Carlo framework to predict stochastic strain fields, critical locations, and critical loads in the specimens. The results from the FE Monte-Carlo analysis provide a good qualitative agreement with the experimental data, suggesting that our framework can be used for structural design of TBDC structures.
Alves M, Pimenta S, 2020, Analysing the effect of fibre waviness on the stiffness of tow-based discontinuous composites
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. Tow-based discontinuous composites (TDBCs) are a particular type of discontinuous composites and are becoming a growing class in high-performance materials. These materials consist of carbon-fibre tows dispersed in a polymeric matrix, resulting in a microstructure that has an inherent 3D nature, with the tows presenting waved configurations. This work aims to develop a microstructure generator able to recreate the characteristic features of the microstructure of TBDCs, such as tow waviness and local thickness and fibre content variations; in addition, flexibility in terms of in-plane tow orientations is also considered, as the distributions of the latter are defined by orientation tensors. The microstructure generator is able to recreate representative cross-sections of these materials, and also out-of-plane angle distributions, for any type of in-plane tow orientations considered. Furthermore, the effect of the tow waviness on the stiffness of these materials is assessed, and a parametric study on the effect of the tow geometry on the in-plane stiffness reduction is carried out.
Alves M, Pimenta S, Carlstedt D, et al., 2020, Thin ply sheet molding compound enables thin laminates with properties as of continuous fibers
In a research collaboration with Chalmers University of Technology, KTH Royal Institute of Technology (SWE) and Imperial College (UK), Oxeon AB has developed ultrathin carbon fiber sheet molding compound (SMC) products for high performance, thin laminate and ease of manufacture composite applications. Said SMC products are based on ultrathin (0.02 mm or 0.0008 in) Spread Tow Tapes that are cut by length and randomly distributed in order to obtain a preform with an in-plane isotropy in either dry or pre-impregnated form displaying the previously never seen minimum cured plate thickness of about 0.5 mm. Recent work has demonstrated that these SMC materials can reach high stiffness and strength making them good alternatives to metal alloys or even continuous fiber composites. In the conduced work, SMC composites were manufactured using ultra-thin tapes of high modulus and ultrahigh modulus fibers having a large length-to-thickness ratio. The paper will describe how these SMC products lead to high stiffness and to significant increase in strength compared to commercially available SMC materials.
Deng X, Kinloch AJ, Pimenta S, et al., 2020, Toughening epoxy composites using nano- And microcellulose modifiers
© CCM 2020 - 18th European Conference on Composite Materials. All rights reserved. The fracture properties and toughening mechanisms of cellulose- and cellulose-rubber hybrid-modified epoxy polymers and glass-fibre (GF) composites are investigated. The cellulose modifiers used are microcrystalline cellulose (MCC) and cellulose nanocrystals (CNC), and the rubber modifiers are carboxyl-terminated butadiene-acrylonitrile (CTBN) and core-shell rubber (CSR). The toughening mechanisms of the MCC-epoxy and CNC-epoxy were identified to be crack deflection, shear band yielding, particle rupture or pull-out and debonding of the cellulose particles, which was followed by plastic void growth. An additive toughening effect is observed for the hybrid polymers. Analytical modelling of the fracture energies showed that the particle pull-out toughening contribution is negligible for CNC-epoxy, and the particle debonding and rupture toughening contributions are negligible for MCC-epoxy. The GF composites were manufactured using the wet-layup process. Cellulose modifiers did not increase the composite propagation fracture energy (GC,prop) but slight increases in GC,prop occurred for the CNC hybrids. Increases in the fibre-matrix adhesion reduced the fibre toughening mechanisms in the composites that were modified with only MCC or CNC. The crack tip deformation zone is smaller than the MCC particles, reducing their toughening ability in the GF composites.
Martulli LM, Muyshondt L, Kerschbaum M, et al., 2019, Carbon fibre sheet moulding compounds with high ine-mould flow: Linking morphology to tensile and compressive properties, Composites Part A: Applied Science and Manufacturing, Vol: 126, Pages: 1-16, ISSN: 1359-835X
In-mould flow during manufacturing of Sheet Moulding Compounds (SMCs) heavily affects the material microstructure and its mechanical properties. This influence is studied here for carbon SMCs on panels compression moulded with limited charge coverage. The high in-mould flow caused severe in-plane tow distortions, while their planarity was preserved. Flow induced fibre orientation plays a paramount role in the material failure, whereas local manufacturing defects had no discernible influence. The properties difference between specimens with preferential orientation of 0° and 90° was 150% for tensile stiffness, 260% for tensile strength, 120% for compressive stiffness and 32% for compressive strength. The compressive strength and failure strain for 45° and 90° specimens were higher than those for tension, and comparable for 0° specimens. Compressive and tensile moduli were similar for specimens with the same orientation. A clear link between SMCs manufacturing and mechanical performance is highlighted, together with its implications on structural design.
Pascoe J-A, Pimenta S, Pinho ST, 2019, Interlocking thin-ply reinforcement concept for improved fracture toughness and damage tolerance, Composites Science and Technology, Vol: 181, ISSN: 0266-3538
An original concept for improving the delamination resistance and damage tolerance of a composite laminate is proposed. The concept is to insert interlocked thin-ply reinforcement units between the laminae. Each reinforcement unit consists of two thin-ply layers with tabs cut into one layer, and slits cut into the other layer. The slits, and the long axis of the tabs, are parallel to the fibre direction in their respective layers. The two thin-ply layers are placed together, and the tabs are inserted through the slits, creating an interlocked reinforcement unit.The effect of the reinforcement units was quantified via mode I (DCB) and mode II (4ENF) fracture toughness tests, as well as compression after impact tests. Mode I propagation fracture toughness was increased by 77.6%, while mode II fracture toughness was not affected. In the compression after impact tests, an 11.4% reduction in delamination area was achieved but this only resulted in a 5.1% increase in CAI strength.
Li Y, Pimenta S, 2019, Development and assessment of modelling strategies to predict failure in tow-based discontinuous composites, Composite Structures, Vol: 209, Pages: 1005-1021, ISSN: 0263-8223
Tow-based discontinuous composites (TBDCs) are a growing class of materials that combine manufacturability, light-weight, and high performance. This study proposes multi-scale modelling approaches to predict the tensile strength and failure envelopes of tow-based discontinuous composites, by representing the actual composite (with randomly-oriented tows) as an equivalent ply-by-ply laminate. Several modelling approaches are considered for the different scales, including (i) a stochastic bi-linear shear-lag formulation accounting for the random location of tow-ends and matrix cracking, (ii) a novel failure criterion for a discontinuous uni-directional ply accounting for the interaction between tow pull-out and transverse failure, and (iii) a ply-discount method or a maximum strain energy criterion for the final failure of the composite. The model computes full failure envelopes for ply-by-ply laminates equivalent to TBDCs within minutes, and the results show good agreement with experimental data.
Alves M, Carlstedt D, Asp L, et al., 2019, Ultra-thin and stiff randomly-oriented discontinuous composites
© 2019 by DEStech Publications, Inc. and American Society for Composites. All rights reserved. This paper presents experimental and numerical results for tensile strength of tow based discontinues composite (TBDC) plates manufactured using ultra-thin fibre tapes of high stiffness carbon fibres. Numerical models were used to explore the design space of these materials, in order to identify the optimal tow properties that maximise the strength of TBDCs. The experimental show good agreement with the numerical predictions and demonstrate a significant increase in the tensile strength by reducing the tow thickness and increasing the stiffness of the fibres. Strength increases of up to 100%, compared with a commercially available material system, are found, illustrating the highly promising potential of this type of material.
Alves M, Carlstedt D, Asp L, et al., 2019, Ultra-thin and stiff randomly-oriented discontinuous composites
This paper presents experimental and numerical results for tensile strength of tow based discontinues composite (TBDC) plates manufactured using ultra-thin fibre tapes of high stiffness carbon fibres. Numerical models were used to explore the design space of these materials, in order to identify the optimal tow properties that maximise the strength of TBDCs. The experimental show good agreement with the numerical predictions and demonstrate a significant increase in the tensile strength by reducing the tow thickness and increasing the stiffness of the fibres. Strength increases of up to 100%, compared with a commercially available material system, are found, illustrating the highly promising potential of this type of material.
Pascoe JA, Pimenta S, Pinho ST, 2019, TIGR nacre: Damage tolerance through damage diffusion
© 2019 by DEStech Publications, Inc. and American Society for Composites. All rights reserved. We present a new hybrid CFRP concept, aimed at increasing the energy absorption capacity of the material by diffusing damage through-out the laminate. To achieve this, we combine thin-ply CFRP layers, cut into interlocking tiles, with titanium interlayers. Uniaxial tension tests and bending tests on a preliminary design iteration showed that damage initiation and initial propagation were successfully achieved, but damage propagation localized during further loading. Final failure was triggered by strain concentrations in the titanium layers, which caused the titanium failure strain to be locally exceeded. The key to achieving higher laminate ultimate strain is to prevent or ameliorate these strain concentrations in the titanium layers.
Finley JM, Shaffer MSP, Pimenta S, 2019, Intelligent optimisation of aligned discontinuous composites
© 2019 by DEStech Publications, Inc. and American Society for Composites. All rights reserved. Aligned discontinuous composites offer a tailorable structural response, as their mechanical behaviour can be tailored by adjusting their microstructure. However, the stochastic nature of their microstructure, and the myriad permutations of different constituent properties makes optimisation of these materials difficult. In this work, an accurate yet efficient virtual testing framework is combined with an intelligent Bayesian optimisation routine to maximise the initial stiffness, ultimate strain, and ultimate strength of aligned discontinuous composites.
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