The rising demand to reduce fuel consumption and the continuous increase of materials and manufacturing costs has obliged aircraft manufacturers to boost the use of composite materials and to optimise the manufacturing methods. Foam core sandwich structures combine the advantages of high bending properties with low manufacturing costs when liquid composite processes are used. However, the use of foam core sandwich structures is not widespread in aircraft applications due to the better weight-specific performance of honeycomb cores and the susceptibility to impact loading. In this context, pin reinforcements are added to the foam core to improve its mechanical properties and its damage tolerance. This work contributes to the understanding of the mechanical behaviour of pin-reinforced foam core sandwich structures under static and impact loading. Ultrasonic scan and micro-computed tomography are used to identify the different damage modes. The effect of very low temperature on the damage behaviour under impact loading is investigated. An explicit simulation model to predict the impact response of pin-reinforced foam core sandwich structures is also proposed.

Marine Composites: Design and Performance presents up-to-date information and recent research findings on the application and use of advanced fibre-reinforced composites in the marine environment. Following the success of their previously published title: Marine Applications of Advanced Fibre-reinforced Composites which was published in 2015; this exemplary new book provides comprehensive information on materials selection, characterization, and performance. There are also dedicated sections on sandwich structures, manufacture, advanced concepts, naval architecture and design considerations, and various applications. The book will be an essential reference resource for designers, materials engineers, manufactures, marine scientists, mechanical engineers, civil engineers, coastal engineers, boat manufacturers, offshore platform and marine renewable design engineers. - Presents a unique, high-level reference on composite materials and their application and use in marine structures - Provides comprehensive coverage on all aspects of marine composites, including the latest advances in damage modelling and assessment of performance - Contains contributions from leading experts in the field, from both industry and academia - Covers a broad range of naval, offshore and marine structures

This thesis deals with the fibre impregnation of a carbon fibre reinforcement by a Sheet Moulding Compound (SMC). In the beginning, the carbon fibre reinforcement has no impregnation. Instead, the impregnation of the carbon fibre is performed by the resin within the SMC material during compression moulding. The combination leads to a Hybrid SMC composite, which is characterized by a high design freedom, good mechanical properties, and high production rates at the same time. The main objective of this study is the development of an analytical impregnation model for Hybrid SMC composites. The impregnation model predicts the final void content with regard to the properties of the semi-finished products and the process implementation. The fibre impregnation is influenced by the viscosity of the SMC material, the processing compression, the permeability, and the thickness of the carbon fibre reinforcement. Among all these parameters, the viscosity is an essential factor for the fibre impregnation, because it is dependent on the temperature and the time. The final impregnation model is developed by an approach of fluid dynamics to track the flow front particles within the SMC material during compression moulding. At the same time, experiments are realized and the void content is determined by using microscopic analysis of the Hybrid SMC composites. The evaluated void contents of the experiments are used to compare the results with the impregnation model. All in all, the investigations have led to an analytical impregnation model with a high accuracy. A deviation of 5% for more than 82% of the specimens was achieved.

Sandwich Structural Composites: Theory and Practice offers a comprehensive coverage of sandwich structural composites. It describes the structure, properties, characterization, and testing of raw materials. In addition, it discusses design and process methods, applications and damage assessments of sandwich structural composites. The book: Offers a review of current sandwich composite lamination processes and manufacturing methods Introduces raw materials, including core materials, skin reinforcements, resin substrates and adhesives Discusses sandwich structure characterization, finite element analysis of the structures, and product design and optimization Describes benefits other than structural, including acoustic, thermal, and fire Details applications in various industries, including aerospace, wind energy, marine ships, recreational boats and vehicles, sport equipment, building construction, and extreme temperature applications The book will be of benefit to industrial practitioners, researchers, academic faculty, and advanced students in materials and mechanical engineering and related disciplines looking to advance their understanding of these increasingly important materials.

Structural carbon fiber reinforced plastic parts are usually manufactured through autoclave processing for high-performance aerospace applications. Today’s aerospace composite manufacturing techniques require high quality with robust manufacturing processes. Manufacturing process simulation enables the investigations of physical effects and manufacturing process mechanisms. This approach has been increasingly used to predict and optimize the manufacturing process for high part quality at low manufacturing costs. Owing to a complicated manufacturing environment involving multi-physics characteristics, there is a critical need to develop an efficient and cost-effective numerical methodology with a systematic study. This thesis contributes to the systematic investigations of the process modeling, simulation, thermal measurement, and optimization in composite manufacturing of autoclave processing. The method provides a correct and efficient thermal analysis and optimization in autoclave processing to achieve better process control and ensure the quality of composite parts. The presented framework can be applied directly in autoclave production with larger dimensions and full-scale tools for aerospace structures. The developed methodology allows quick delivery guidelines of production plans and optimization strategies for composite manufacturing in a highly useful and cost-effective way, thereby reducing the cost in the design and manufacturing phase. Since July 2017, Mr. Junhong Zhu has been working as a research assistant in the department of modeling and simulation at the FIBRE (Faserinstitut Bremen e.V.) at the University of Bremen. He deals with the process modeling and simulation in composite manufacturing of autoclave processing. His research focuses on numerical methods, such as computational fluid dynamics and finite element methods, muti-physics coupling schemes, and process optimization. He is also interested in the use of artificial intelligence in the manufacturing process.

Sandwich structures are an economically and structurally efficient way of designing large integral composite parts. In the aerospace industry pre-impregnated face sheets and honeycomb core structures can be considered as industry standard while e.g. naval structures and wind turbine blades typically use vacuum infusion technology with polymer foam cores. Application of the less costly infusion technology in the aeronautical industry requires a thorough understanding of the damage tolerance including low velocity impact as a frequent source of damaging events. At low impact energies damage in composite foam core sandwich structures is limited to core crushing and local face sheet delaminations. Higher impact energies may initiate the competing failure modes face sheet rupture and core shear failure depending on impact, geometric and material parameters. Face sheet rupture leads to severe local damage with typically good visibility, while core shear failure leads to cracks and rear face sheet debonding of the foam core with less visibility. This work investigates the low velocity impact response of sandwich structures with carbon fiber reinforced plastic (CFRP) face sheets and a polymeric foam core using experiments at room temperature and at -55° Celsius. An analytically derived failure mode map is presented as a simple tool for design guidelines while the explicit finite element method is applied for a more detailed description of the sandwich impact process. Both models are used to analyze the impact response and describe relevant sensitivity parameters of sandwich structures.

Incorporating Sustainable Practice in Mechanics of Structures and Materials is a collection of peer-reviewed papers presented at the 21st Australasian Conference on the Mechanics of Structures and Materials (ACMSM21, Victoria, University, Melbourne, Australia, 7th 10th of December 2010). The contributions from academics, researchers and practisin