A Precise Prediction of the Chemical and Thermal Shrinkage during Curing of an Epoxy Resin.

A precise prediction of the cure-induced shrinkage of an epoxy resin is performed using a finite element simulation procedure for the material behaviour. A series of experiments investigating the cure shrinkage of the resin system has shown a variation in the measured cure-induced strains. The observed variation results from the thermal history during the pre-cure.

Tailored cure profiles for simultaneous reduction of the cure time and shrinkage of an epoxy thermoset.

Defining the specific cure profile of thermosetting polymers is an important aspect in many applications where the mechanical performance and appearance of components can be affected. Cure-induced strains or stresses from the shrinkage of thermosets lead to reduced performance due to accelerated damage or discarded products due to distortions. This research focuses on validating a proposed modelling framework, simulating the load-transferring part of the curing process affecting the mechanical performance.

Dataset for scanning electron microscopy based local fiber volume fraction analysis of non-crimp fabric glass fiber reinforced composites.

This dataset includes four large field-of-view scanning electron microscopy (SEM) images together with associated Matlab scripts aimed for the analysis used in the joint publication. Each of the four stitched images is generated from a large number (between 15500 and 24500) high-resolution (195nm/pixel) scans, which have been stitched into four images stored as tiff-files. The images show the cross-section of fiber bundles in composite laminate and are well-suited for local fiber volume determination.

Influence of Test Specimen Geometry on Probability of Failure of Composites Based on Weibull Weakest Link Theory.

This paper presents an analytical model that quantifies the stress ratio between two test specimens for the same probability of failure based on the Weibull weakest link theory. The model takes into account the test specimen geometry, i.e.

Experimental Method for Tensile Testing of Unidirectional Carbon Fibre Composites Using Improved Specimen Type and Data Analysis.

This paper presents an experimental method for tensile testing of unidirectional carbon fibre composites. It uses a novel combination of a new specimen geometry, protective layer, and a robust data analysis method. The experiments were designed to test and analyze unprotected (with conventional end-tabs) and protected (with continuous end-tabs) carbon fibre composite specimens with three different specimen geometries (straight-sided, butterfly, and X-butterfly).

Scanning electron microscopy datasets for local fibre volume fraction determination in non-crimp glass-fibre reinforced composites.

The fatigue damage evolution depends on the local fibre volume fraction as observed in the co-submitted publication [1]. Conventionally, fibre volume fractions are determined as an averaged overall fibre volume fraction determined from small cuts of the laminate. Alternatively, automatically stitching of scanning electron microscopy (SEM) images can make high-resolution scans of large cross-section area with large contrast between the polymer and glass-fibre phase.

Dataset of non-crimp fabric reinforced composites for an X-ray computer tomography aided engineering process.

This data in brief article describes a dataset used for an X-ray computer tomography aided engineering process consisting of X-ray computer tomography data and finite element models of non-crimp fabric glass fibre reinforced composites. Additional scanning electron microscope images are provided for the validation of the fibre volume fraction. The specimens consist of 4 layers of unidirectional bundles each supported by off-axis backing bundles with an average orientation on ±80° The finite element models, which were created solely on the image data, simulate the tensile stiffness of the samples.

Time-Lapse Helical X-ray Computed Tomography (CT) Study of Tensile Fatigue Damage Formation in Composites for Wind Turbine Blades.

Understanding the fatigue damage mechanisms in composite materials is of great importance in the wind turbine industry because of the very large number of loading cycles rotor blades undergo during their service life. In this paper, the fatigue damage mechanisms of a non-crimp unidirectional (UD) glass fibre reinforced polymer (GFRP) used in wind turbine blades are characterised by time-lapse ex-situ helical X-ray computed tomography (CT) at different stages through its fatigue life. Our observations validate the hypothesis that off-axis cracking in secondary oriented fibre bundles, the so-called backing bundles, are directly related to fibre fractures in the UD bundles.

Ex-situ X-ray computed tomography, tension clamp and in-situ transilluminated white light imaging data of non-crimp fabric based fibre composite under fatigue loading.

The data published with this paper is obtained during fatigue testing of a unidirectional non-crimp fabric based glass fibre composite by means of ex-situ X-ray CT and in-situ transilluminated white light imaging experiments. The data experimentally shows the damage initiation and progression under fatigue loading both in terms of off-axis cracks in the thin supporting backing fibre bundles and fibre fractures in the load carrying fibre bundles. X-ray CT data comparing the loaded and unloaded state of damage regions by means of a tension clamp solution are also published with this paper.

A multimodal data-set of a unidirectional glass fibre reinforced polymer composite.

A unidirectional (UD) glass fibre reinforced polymer (GFRP) composite was scanned at varying resolutions in the micro-scale with several imaging modalities. All six scans capture the same region of the sample, containing well-aligned fibres inside a UD load-carrying bundle. Two scans of the cross-sectional surface of the bundle were acquired at a high resolution, by means of scanning electron microscopy (SEM) and optical microscopy (OM), and four volumetric scans were acquired through X-ray computed tomography (CT) at different resolutions.

Ex-situ X-ray computed tomography data for a non-crimp fabric based glass fibre composite under fatigue loading.

The data published with this article are high resolution X-ray computed tomography (CT) data obtained during an ex-situ fatigue test of a coupon test specimen made from a non-crimp fabric based glass fibre composite similar to those used for wind turbine blades. The fatigue test was interrupted four times for X-ray CT examination during the fatigue life of the considered specimen. All the X-ray CT experiments were performed in the region where unidirectional fibre fractures first became visible, and thereby include the damage progression in 3D in this specific region during fatigue loading of the specimen.

Computational Modelling of Materials for Wind Turbine Blades: Selected DTU Wind Energy Activities.

Computational and analytical studies of degradation of wind turbine blade materials at the macro-, micro-, and nanoscale carried out by the modelling team of the Section Composites and Materials Mechanics, Department of Wind Energy, DTU, are reviewed. Examples of the analysis of the microstructural effects on the strength and fatigue life of composites are shown. Computational studies of degradation mechanisms of wind blade composites under tensile and compressive loading are presented.

A method to investigate the biomechanical alterations in Perthes' disease by hip joint contact modeling.

Perthes' disease is a destructive hip joint disorder characterized by malformation of the femoral head in young children. While the morphological changes have been widely studied, the biomechanical effects of these changes still need to be further elucidated. The objective of this study was to develop a method to investigate the biomechanical alterations in Perthes' disease by finite element (FE) contact modeling using MRI.