Abstract

The recent trend to replace Body-in-White components with carbon fibre laminates, known as “Body in Black”, has been taking hold in new vehicle designs. This is how various hybrids with a thermoplastic matrix are born, such as CAPET, which has titanium with carbon fibres in PEEK, CAPAAL, which has aluminium with carbon fibres and glass in PA 6, CATPUAL based on CAPAAL, with thermoplastic polyurethane matrix and aluminium sheets. This project includes the study and design of hybrid laminates that can replace a monolithic steel sheet. Analytical models based on the classical laminate theory and models based on the rule of mixtures were used to predict the mechanical behaviour of the material. The structural behaviour of a semi-product was analysed using finite element simulations. The results show that it is possible to obtain a weight reduction between 13% and 22% when using a hybrid laminate, but it is required to increase the thickness of the lamina up to 3 times compared to the metal. Subsequently, studies were carried out to measure the wetness of the surface and the adhesion resistance of a carbon fibre prepreg with PA6 matrix on aluminium. A life cycle analysis (LCA) of hybrid laminates designed to observe the environmental impact on energy consumption and carbon footprint was carried out. 

Abstract

En el presente trabajo se ha caracterizado la tenacidad a la fractura interlaminar en modo I y modo II de un compuesto laminado híbrido formado por capas reforzadas con fibras de carbono y capas reforzadas con fibra de vidrio.

Para la realización de los ensayos se han utilizado laminados unidireccionales, y la secuencia de apilamiento ha sido elegida con el propósito de conseguir modos de fractura puros en los ensayos.

La caracterización mecánica se ha llevado a cabo mediante ensayos de flexión en tres puntos con diferentes luces teniendo en cuenta los efectos de indentación, cortante y la rotación de los soportes.

Los ensayos de fractura interlaminar en Modo I y Modo II se han realizado mediante el ensayo ADCB (Asymmetric Double Cantilever Beam) y AENF (Asymmetric End Notched Flexure) respectivamente, considerando también los efectos del cortante, deformación local y las rotaciones debidas a la flexión. Los datos se han obtenido mediante un modelo analítico de reciente publicación que permite hallar la curva de resistencia para cada dato carga-desplazamiento obtenido de la máquina de ensayos.

In this work, the Mode I and Mode II interlaminar fracture toughness of a hybrid laminate composite consisting of carbon fiber-reinforced layers and glass fiber-reinforced layers was characterized.

Unidirectional laminates were used for the tests, and the stacking sequence was chosen with the aim of achieving pure fracture modes in the tests.

Mechanical characterization was carried out using three-point bending tests with different spans, taking into account the effects of indentation, shear, and support rotation.

Mode I and Mode II interlaminar fracture tests were performed using the ADCB (Asymmetric Double Cantilever Beam) and AENF (Asymmetric End Notched Flexure) tests, respectively, also considering the effects of shear, local deformation, and rotations due to bending. The data were obtained using a recently published analytical model that allows the resistance curve to be found for each load-displacement data obtained from the testing machine.