Integration and evaluation of a meander-shaped fibre-optical sensor in a GFRP leaf spring

Fibre-reinforced plastics experience an increasing attention also in the non-aerospace sector. However, the detection of possible internal damage of safety-relevant components remains a challenge. In previous work, a meander-shaped sensor layout with a single fibre-optical sensor was proposed as a particularly efficient and reliable layout and its suitability was demonstrated in coupon tests. In the present work, the approach was transferred to a leaf spring made of glass fibre reinforced plastics and investigated in an extensive test campaign with a realistic test setup. The investigations show the particular suitability of the proposed meander-shaped sensor layout for simultaneous loads monitoring and structural health monitoring.

Comparison of Mechanical Properties of Hemp-Fibre Biocomposites Fabricated with Biobased and Regular Epoxy Resins

Bio- and green composites are mainly used in non-structural automotive elements like interior panels and vehicle underpanels. Currently, the use of biocomposites as a worthy alternative to glass fibre-reinforced plastics (GFRPs) in structural applications still needs to be fully evaluated. In the current study, the development of a suited biocomposites started with a thorough review of the available raw materials, including both reinforcement fibres and matrix materials. Based on its specific properties, hemp appeared to be a very suitable fibre. A similar analysis was conducted for the commercially available biobased matrix materials. Greenpoxy 55 (with a biocontent of 55%) and Super Sap 100 (with a biocontent of 37%) were selected and compared with a standard epoxy resin. Tensile and three-point bending tests were conducted to characterise the hemp-based biocomposite.

The Drilling Investigation of Glass Fibre Reinforced Plastic

Nowadays the usage of glass fibre-reinforced plastics (GFRP) is increasing. The cutting of these materials entails several problems, e.g. the strong abrasive wear effect of the glass fibres or delamination effects. In this paper, we examine the results of drilling experiments on a 10 mm thick GFRP which included 26 layers. The cutting parameters were changed over a wide range. During the experiments, we measured the average surface roughness parameter (Ra). After the tests, we examined the effect of the cutting parameters on the measured roughness values. We created two types of predictive model to estimate the roughness parameter and compared their applicability.