Deconsolidation of thermoplastic prepreg tapes during the heating phase of LAFP: An experimental investigation into the effect of a resin-rich surface and tape pre-tension

Laser-assisted automated fiber placement (LAFP) is a promising additive manufacturing technique for the production of large aerospace components. Thermoplastic prepreg tapes will be placed ply-by-ply on top of a mould and in-situ consolidated. This is beneficial for higher production rates. The mechanical performance of thermoplastic composite...

Novel thermomechanical characterization for shrinkage evolution of unidirectional semi-crystalline thermoplastic prepregs (PPS/CF) in melt, rubbery and glassy states

Shrinkages, distortions and high residual stresses in the thermoplastic composite parts are induced due to high processing temperature, anisotropy, and fiber–matrix shrinkage mismatch. In this paper the shrinkages have been investigated experimentally and modeled by thermo-mechanical constitutive equations for PolyPhenylene Sulfide (PPS) and...

Strain-based delamination prediction in fatigue loaded CFRP coupon specimens by deep learning and static loading data

Machine learning (ML) methods for the structural health monitoring (SHM) of composite structures rely on sufficient domain knowledge as they typically demand to extract damage-sensitive features from raw data before training the ML model. In practice, prior knowledge is not available in most cases. Deep learning (DL) methods, on the other...

Thermal deconsolidation of thermoplastic prepreg tapes during Laser-Assisted Fiber Placement

The automation of thermoplastic composite production and the drive towards out-of-autoclave processes, is of great relevance in the aerospace and lightweight composite structures industry. Hence, there is a crucial need for developing the current state of material and process understanding, in order to increase the technology readiness levels of...

A large displacement orthotropic viscoelastic model for manufacturing-induced distortions in Fibre Metal Laminates

Distortions and residual stresses are predicted in Fibre Metal Laminates (FMLs) under large deformations. A new modelling procedure is presented for small and large deformation analysis of thermo-viscoelastic problems of orthotropic materials. The material model is implemented in a finite element package which can be used for cure and/or...

A numerical Bayesian-calibrated characterization method for multiscale prepreg preforming simulations with tension-shear coupling

Carbon fiber reinforced plastics (CFRPs) are attracting growing attention in industry because of their enhanced properties. Preforming of thermoset carbon fiber prepregs is one of the most common production techniques of CFRPs. To simulate preforming, several computational methods have been developed. Most of these methods, however, obtain...

Experimental and numerical investigation of the strain rate-dependent compression behaviour of a carbon-epoxy structure

The usage of fibre-reinforced composites in automotive body structures is still a rarity. The main goal in body structure development is to design lightweight structures as cost-efficient as possible. This research contributes to the approach of maximal material usage by considering the strength increase of a carbon-epoxy laminate with...

The modeling of fiber metal laminates by thick shell elements

Delamination growth in improved carbon composites under constant amplitude fatigue loading

Constant amplitude tension-compression fatigue tests were performed on notched (± 45, 02, 90, 02)s coupon specimens of the composite systems T300/F593, T400H/6376, T800H//5245C and IM6/APC-2. Delamination damage growth as a function of the number of fatigue cycles was determined using the ultrasonic C-scan technique. Considering the resistance...

Determination of the resin content in DSC prepreg samples using thermal analysis techniques

Determination of the heat of reaction during the cure of the resin in carbon fibre reinforced epoxy prepreg using Differential Scanning Calorimetry resulted in considerable scatter with the measurements were done on prepreg samples. Differences in resin content between the DSC prepreg samples were suspected to be the main cause of the observed...

Impact/fatigue performance of a (±45₂, O₄)s type carbon/epoxy laminate

In this report the results of an impact damage and fatigue investigation are discussed. Comparative impact tests have been carried out on a solid (± 45₂,O ₄)s carbon/epoxy base laminate and the same type of laminate covered with outer layers of glass, aramid or carbon fabric. In addition an Aramid Reinforced Aluminium Laminate (ARALL) was...