1,721,010 research outputs found
Understanding heterogeneity in discontinuous compression composite materials for high-volume applications
No full textTo understand the mechanisms contributing to material heterogeneity in discontinuous compression moulded composite materials, a data rich study combining digital image correlation (DIC), thermoelastic stress analysis (TSA) and X-ray computed tomography (CT) is presented. Initial results show that DIC and TSA are capable of capturing variability in surface strains and stresses when subjected to a cyclic load, and X-ray CT has been used to quantify volumetric variability in local resin volume content and distribution of local fibre orientations, which all contribute to the complex response detected on the component surface
Data for: Image-enhanced modelling of residual compressive after impact strength in laminated composites
No full textTabulated data for: Image-enhanced modelling of residual compressive after impact strength in laminated composites
Results contain the following outputs from simulations:
•Damage area vs. force and out-of-plane deflection data
•Load vs. strain energy release rate data
•Failure load predictions
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Image-enhanced modelling of residual compressive after impact strength in laminated composites
No full textThis study implements key mechanisms and parameters observed from the previous compression after impact (CAI) experimental studies into finite element models, to study their effects parametrically on residual compression strength. The mechanisms and parameters include: impact damage area, the role of intact interfaces within the overall damaged region (identified here as the “undamaged cone”), interlaminar toughness, and the extent of permanent out-of-plane deformation. The findings highlight that within the limits observed experimentally, in addition to the size of the damaged area, interlaminar toughness and the extent of permanent out-of-plane deformation strongly affect CAI strength (by up to ~100% for a given damage area), with toughness playing a more significant influence than permanent out-of-plane deformation. For the first time, and contrary to much of the literature, the significant role of the undamaged cone is evidenced and quantified
A finite element study on the effects of toughness and permanent out-of-plane deformation on post-impact compressive strength
No full textThis study applies mechanisms observed from previous work (the undamaged cone, toughness and extent of permanent out-of-plane deformation) to parametrically study their effects on residual compression after impact (CAI) strength using finite element models. Based on previous experimental work, tougher material systems exhibited up to 30% greater CAI strength for a given damage area. Based on this, it is necessary to understand what other parameters, beyond damage area, contribute to a loss in CAI strength. Finite element models were conducted in ABAQUS explicit. Delamination growth was modelled using the virtual crack closure technique (VCCT). This study found that systems containing an undamaged cone led to an increased load prior to buckling resulting in lower 0° peak compressive stresses and lower strain energy release rates forming at the outer edges of the delamination zone. In certain configurations, delamination growth into the undamaged cone occurred and was shown to negatively affect the post-buckled response. Overall, the effects of both toughness and permanent out-of-plane deformation was shown to affect CAI failure load by up to ~50% for a given damage diameter. It is also apparent that toughness played a more significant influence than the extent of permanent out-of-plane deformation
On the source of the thermoelastic response from orthotropic fibre reinforced composite laminates
Full text linkIn thermoelastic stress analysis (TSA) of orthotropic laminated polymer composites, heat transfer influences the measured stress induced temperature change, or ‘thermoelastic response’. The composite constituents, including different fibre types, fibre geometry, ply thickness and resin systems, in combination with the manufacturing process means that, even for nominally identical materials, different conditions are generated for heat transfer. Hence, definitively identifying the ‘source’ of the thermoelastic response for a general composite laminate has remained elusive. A procedure based on the simultaneous application of digital image correlation (DIC) and TSA is devised that enables the source of the thermoelastic response to be established categorically. In glass fibre laminates, it is shown that heat conduction cannot take place so the thermoelastic response emanates from the surface resin rich layer. In similar carbon fibre laminates, adiabatic conditions are only met at higher frequencies with the response emanating from the orthotropic surface ply
Understanding the mechanisms of root-reinforcement in soils: soil shear tests using X-ray computed tomography and digital volume correlation
No full textSoil containing plant roots may be expected to exhibit a greater shearing resistance compared with the same ‘unreinforced’ soil, providing enhanced stability and effective erosion control, particularly for earth slopes. To be able to rely on the improved shearing resistance and stiffness of root-reinforced soils, it is important to understand and quantify the effectiveness of root reinforcement. This requires sophisticated multiscale models, building understanding at different length scales, from individual soil-root interaction through to full soil-profile or slope scale. One of the challenges with multiscale models is ensuring that they are representative of real behaviour, and this requires calibration to detailed high-quality experiments. The focus of the work presented was to capture and quantify root-reinforcement behaviour and associated soil and root deformation mechanisms during direct shear at the macroscopic to millimetre length scales. A novel shear box was developed to operate within a large-scale X-ray computed tomography (CT) scanner. Tests were interrupted to be scanned at a series of shear displacements from 0-20 mm to capture the chronology of behaviour in three-dimensions. Digital volume correlation (DVC) was applied to the CT dataset to obtain full-field 3D displacement and strain component information. The study demonstrates feasibility of the technique and presents preliminary DVC results
Real-time through-thickness and in-plane strain measurement in carbon fibre reinforced polymer composites using planar optical Bragg gratings
No full textA new strain sensor is proposed which can measure both through-thickness and in-plane strains within a laminated fibre-reinforced composite material. The planar sensor uses novel embedded planar optic sensors and is demonstrated on a carbon fibre composite test coupon. The planar optical sensor was fabricated via flame hydrolysis deposition and was physically machined to reduce the substrate thickness to <50µm. Strain components are decoupled through monitoring the transverse electric and transverse magnetic effective refractive indices of two orthogonal planar waveguides. The work investigates if the embedded planar sensors have any mechanical knock down effects on the composite structure and demonstrates their effectiveness at decoupling three orthogonal strain components
Effects of oxygen-related damage on dwell-fatigue crack propagation in a P/M Ni-based superalloy: from 2D to 3D assessment
No full textThis dataset includes the data presented in the journal paper, Effects of oxygen-related damage on dwell-fatigue crack propagation in a P/M Ni-based superalloy: From 2D to 3D assessment published in the International Journal of Fatigue, Volume 99, Part 1, June 2017, Pages 175–186, http://dx.doi.org/10.1016/j.ijfatigue.2017.03.003
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Data set for Thermoelastic Response Data
No full textData to support article "On the source of the thermoelastic response from orthotropic fibre reinforced composite laminates' in the journal "Composites Part A".
Data contains Thermoelastic Stress Analsys, Digital Image Correlation, strain gauges and test machine data for GFRP and CFRP samples tested. There is a readme file for each type of data inside the subfolders.</span
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