VIII Conference on Mechanical Response of Composites最新文献

{"title":"Methodology for Prediction of Transverse Crack Saturation Density and Diffuse Delamination Onset in Laminates","authors":"M. Shevchuk, C. Schuecker","doi":"10.23967/composites.2021.015","DOIUrl":"https://doi.org/10.23967/composites.2021.015","url":null,"abstract":"When a multidirectional laminate is subjected to unidirectional quasi-static loading, an early stage of damage is dominated by formation of transverse matrix cracks, until eventually, saturation crack density is reached, giving rise to diffuse delamination starting from the crack tips. To evaluate the saturation density, a generalized plane strain model for orthotropic composite lamina is developed. Geometry of the model is taken into account by means of a representative unit cell containing a transverse crack (see Fig. 1). The evaluation is carried out in an iterative manner. After the length of the unit cell, defined as half the distance between two neighbouring cracks, is initialized, a load increment is applied. As a result, either a new transverse crack is created when the longitudinal stress reaches its ultimate value, leading to the update in the length of unit cell, or the delamination is initiated if the delamination onset criterion is met. If both events fail to take place, the load is increased for the next iteration set up. A bimaterial interface delamination experiences mixed mode conditions near the tip of the matrix crack, creating the necessity to evaluate the mode mixity and adopt the appropriate delamination onset criterion. The strain energy release rate (SERR) for different delamination modes was evaluated using virtual crack closure technique and compared to the SERR obtained using a global strain energy approach. The predicted delamination onset is in good agreement with the available experimental results for the cross-ply laminates (see Fig. 2). Application of the approach to other layup configura-tions will also be investigated","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127015532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Analysis of Fatigue Damage Behavior in Fiber Composites under Different Block Loading Conditions","authors":"G. Catalanotti, M. Brod, A. Dean, Sven Scheffler, Raimund Rolfes","doi":"10.23967/composites.2021.024","DOIUrl":"https://doi.org/10.23967/composites.2021.024","url":null,"abstract":"During their lifetime","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"157 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126191075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multidimensional Inverse Differential Quadrature Method for Analysis of Composite Plate Structures","authors":"M. Fagerstr¨om, G. Catalanotti, Hasan M. Khalid, S. O. Ojo, P. M. Weaver","doi":"10.23967/composites.2021.091","DOIUrl":"https://doi.org/10.23967/composites.2021.091","url":null,"abstract":"Mechanics of composite plates are characterised by systems of high-order partial differential equations subject to admissible boundary conditions . Typically, closed form or exact solutions of such high-order systems are rarely feasible or sometimes impossible, thus necessitating a numerical approach. Conventional numerical approaches based on direct approximation of system variables may incur considerable errors subject to high-order numerical differentiation [1]. The inverse differential quadrature method (iDQM) is a new promising approach for obtaining numerical solution of high-order systems based on the approximation of higher order derivatives of a function as linear weighted sum of the function derivatives over the discretized domain [2]. To obtain the iDQM coefficients, a novel routine based on the inversion of existing DQM formula is adopted leading to an efficient and numerically stable scheme (known as iDQM-by-inversion ) which retains the accuracies of high-order secondary variables like strains, and consequently stresses, that are prone to numerical error due to differentiation operations [2]. In this study, two-dimensional iDQM scheme is implemented for static analysis of specially or-thotropic composite plate, with inplane dimensions a and b , subjected to uniformly distributed transverse load and simply supported boundary condition on all the edges, based on classical laminated plate theory (CLPT). Stress estimates, shown in figure 1, by iDQM of different orders and DQM, benchmarked against closed-form Navier solutions show good agreement with faster convergence.","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"123 7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126432922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cohesive Zone Based Conformal Meshing and Damage Simulation of Yarn Contacts in Woven Composites","authors":"A. Li, B. Wintiba, J. Remmers, M. Geers, T. Massart","doi":"10.23967/composites.2021.020","DOIUrl":"https://doi.org/10.23967/composites.2021.020","url":null,"abstract":"","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123098394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of a Rate Dependent Model on a UD NCF Carbon/Epoxy Composite","authors":"V. Singh, R. Larsson, R. Olsson, E. Marklund","doi":"10.23967/composites.2021.045","DOIUrl":"https://doi.org/10.23967/composites.2021.045","url":null,"abstract":"To support the modelling of composites under rapid transient loading, e.g. impact, crash, and vibrations, a computational multiscale constitutive model has been developed for the progressive failure of unidirectional carbon fibre composites. The model is computationally efficient and captures anticipated failure modes to an acceptable accuracy. Computational homogenization and micromechanics are utilized in the modelling at the ply scale. A major focus is to predict the strain rate dependent nonlinear constitutive behaviour of unidirectional composite plies [1]. The fibres are assumed transversely isotropic, whereas the polymer is viscoelastic–viscoplastic, including a pressure dependent strength. Degradation of the polymer matrix is described by a recently developed continuum damage mechanics approach [2]. The model has been successfully implemented as a VUMAT subroutine in Abaqus/Explicit. Figure 1 shows FE simulation of strain localization as compared to experimental results of IM7/8552 in dynamic off-axis compression [3]. Reasonable correlation was found between the measured and numerically predicted results.","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123126363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phase-field Based Damage Modelling of 3D-Woven Composites","authors":"C. Oddy, M. Ekh, M. Fagerstrom","doi":"10.23967/composites.2021.084","DOIUrl":"https://doi.org/10.23967/composites.2021.084","url":null,"abstract":"","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133901810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational Modelling of Failure Mechanisms in Fibre Metal Laminates","authors":"Ibrahim H. Abuzayed, Ahmed Saadi, J. L. Curiel-Sosa","doi":"10.23967/composites.2021.007","DOIUrl":"https://doi.org/10.23967/composites.2021.007","url":null,"abstract":"Fibre Metal Laminates (FMLs) are hybrid materials that are composed of thin metal layers reinforced with unidirectional or bi-directional fibre composites. The most common type of FMLs is the glass laminate aluminium reinforced epoxy (GLARE) which comprised aluminium and prepreg layers. FMLs benefit from the properties of both constituents, they are characterised by their low weight, high strength and excellent fatigue resistance [1]. The superior mechanical properties of FMLs made them attractive to the aerospace industry, for example, GLARE is used for the manufacture of the fuselage and leading edges of A380 [1]. FMLs were originally developed to improve the fatigue damage growth resistance of the monolithic metals used for aerospace structures such as aluminium. According to Wu and Yang GLARE shows 10 to 100 times slower crack growth rates compared to Aluminium [2]. The fatigue failure in FMLs, as described by Alderliesten [3], begins with crack initiation and propagation under cyclic loading in a metallic layer followed by delamination between the metal and composite interface. The delamination distributes the stress caused by the cyclic loading over a larger area which decreases the stress in the composite layers and decreases the risk of composite failure i.e. (matrix cracking or fibre splitting) [4]. Therefore, the fibres remain intact and allow the load to be transferred through the composite layer across the crack [3]. This is often referred to as the bridging mechanism, where it plays a significant role in decreasing the crack growth in FMLs.","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129480119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early Stage Temperature Conditions Influence on Micromechanical Features of Thermoset Polymer-based Composite","authors":"J. Vorel, V. Hrbek, M. Šejnoha","doi":"10.23967/composites.2021.026","DOIUrl":"https://doi.org/10.23967/composites.2021.026","url":null,"abstract":"The application of thermoset polymer-based composites is widespread in many engineering fields, such as automotive, aerospace or bioengineering industry. These composites found their civil engineering utilisation, e.g., as post-installed anchoring systems or in concrete and masonry reconstructions. Regardless of the use, environmental conditions imposed on a typical thermoset polymer matrix during casting and early curing stage predetermine properties of the composite in a hardened state. Moreover, unstable environmental conditions that usually occur in civil engineering practice may lead to structural service life reduction or, in the worst case, abrupt failure due to alternated mechanical features. In general,","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130022929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Second-order Computational Homogenisation for Thick Shell Models: Application to Non-linear Multiscale Analysis of Composites","authors":"A. Hii, B. E. Said, S. Hallett","doi":"10.23967/composites.2021.022","DOIUrl":"https://doi.org/10.23967/composites.2021.022","url":null,"abstract":"Advanced composites often have complex material morphology that spans several length scales in the thickness direction, which presents significant challenges for computational analyses. The so-called shell-based computational homogenisation can be used to analyse this class of problems, where it homogenises the nonlinear micro/mesoscopic phenomena using an effective shell model at the macroscale. The homogenisation framework for thin shell models was first proposed by Coenen et al. [1]. Recently, more research efforts have been focused on developing homogenisation techniques for thick shells, to incorporate the effects of through-thickness deformation during scale transition. However, it has been widely reported that classical homogenisation techniques cannot properly represent the macroscopic transverse shear and through-thickness normal strains at the fine scale; and that their homogenised stress resultants are inaccurate when compared to analytical solutions, showing a dependency on the slenderness of the micro/mesomodels [2 – 4]. As such, the proper treatments for macroscopic through-thickness shell quantities during downscaling remain a prominent research challenge. The key contribution of this work is the development of a nonlinear second-order computational homogenisation framework for thick shell models. We have proposed a complete set of minimal boundary conditions, such that the correct average membrane, bending, and most importantly the transverse shear and through-thickness normal strains can be obtained during downscaling. In addition, the corresponding fine scale solution yields the correct stress resultants that are convergent and have no size dependency. The framework also allows for kinematic assumptions — such as the inextensibility and the plane stress conditions (Reissner-Mindlin), constant thickness strain (6-parameter formulation) and linearly varying thickness strain (7-parameter formulation) — to be enforced at the fine scale. Furthermore, full geometric nonlinearity can be","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114778664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calibration and Validation of a Numerical Curing Model Using AS4/8552 Asymmetrical Laminated Composite Plates","authors":"M. Fagerström, G.Catalanotti, T. Koenis, N. V. Hoorn, W. M. V. D. Brink","doi":"10.23967/composites.2021.035","DOIUrl":"https://doi.org/10.23967/composites.2021.035","url":null,"abstract":"During manufacturing of composite materials residual stresses and deformations can result in distortion of the final part. In aerospace manufacturing the use of shimming caused by part distortions during assembly should be minimized. The prediction and minimization of the distortion is even more critical when building on existing parts, e.g. for a repair, as the added material has to conform to the original structure. To predict this distortion due to curing of thermoset carbon-matrix composites a numerical modelling method is employed. This method includes the cure kinetics, the Cure Hardening Instantaneously Linear Elastic (CHILE) pseudo-viscoelastic model [1], and the homogenisation of laminae properties employing the Composite Cylinder Assemblage (CCA) model [2]. This method is implemented in ABAQUS by using the USDFLD and EXPAN subroutines. A prominent issue when accurately modelling the distortion due to curing is the absence of accurate material parameters. To this end, a calibration method is proposed to estimate unknown parameters for the numerical curing model (e.g., the thermal expansion and chemical shrinkage coefficients of the resin). In an experimental campaign AS4/8552 plates have been manufactured with a [90 n 0 m ] asymmetrical layup. The numerical model is calibrated to match the deformation of the asymmetrical plates. In addition, an experiment is performed where the plates have been reheated. At the elevated temperature this leads to a reduction in deformation. With this approach, the effects of thermal expansion have been isolated from the chemical induced deformation, which facilitates direct calibration of the coefficients of thermal expansion. After calibration, the numerical modelling approach is validated using additional asymmetric plates and more complex shaped parts.","PeriodicalId":392595,"journal":{"name":"VIII Conference on Mechanical Response of Composites","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134256020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}