This review paper summarizes the current state-of-art and challenges for the future developments of fiber-reinforced composites for structural applications with multifunctional capabilities. After a brief analysis of the reasons of the successful incorporation of fiber-reinforced composites in many different industrial sectors, the review analyzes three critical factors that will define the future of composites. The first one is the application of novel fiber-deposition and preforming techniques together with innovative liquid moulding strategies, which will be combined by optimization tools based on novel multiscale modelling approaches, so fiber-reinforced composites with optimized properties can be designed and manufactured for each application. In addition, composite applications will be enhanced by the incorporation of multifunctional capabilities. Among them, electrical conductivity, energy storage (structural supercapacitors and batteries) and energy harvesting (piezoelectric and solar energy) seem to be the most promising ones.

Structural composites for multifunctional applications: current challenges and future trends

Structural composites for multifunctional applications: Current challenges and future trends

Computational micromechanics of fiber kinking in unidirectional FRP under different environmental conditions

The development of the latest generation of wide-body passenger aircraft has heralded a new era in the utilisation of carbon-fibre composite materials. One of the primary challenges facing future development programmes is the desire to reduce the extent of physical testing, required as part of the certification process, by adopting a ‘certification by simulation’ approach. A hierarchical bottom-up multiscale simulation scheme can be an efficient approach that takes advantage of the natural separation of length scales between different entities (fibre/matrix, ply, laminate and component) in composite structures. In this work, composites with various fibre/matrix and interlaminar interfacial properties were fabricated using an autoclave under curing pressures ranging from 0 to 0.8 MPa. The microstructure (mainly void content and spatial distribution) and the mechanical properties of the matrix and fibre/matrix interface were measured, the latter by means of nanoindentation tests in matrix pockets, and fibre push-in tests. In addition, the macroscopic interlaminar shear strength was determined by means of three-points bend tests on short beams. To understand the influence of interfacial properties on the intralaminar failure behaviour, a high-fidelity microscale computational model is presented to predict homogenized ply properties under shear loading. Predicted ply material parameters are then transferred to a mesoscale composite damage model to reveal the interaction between intralaminar and interlaminar damage behaviour of composite laminates.

/pdf/the-role-of-interfacial-properties-on-the-intralaminar-and-jk7qtchu7n.pdf

The role of interfacial properties on the intralaminar and interlaminar damage behaviour of unidirectional composite laminates: Experimental characterization and multiscale modelling

Multi-scale computational analysis of unidirectional carbon fiber reinforced polymer composites under various loading conditions

Qualification of Fiber Reinforced Polymer materials (FRP’s) for manufacturing of structural components in the aerospace industry is usually associated with extensive and costly experimental campaigns. The burden of testing is immense and materials should be characterized under different loading states (tension, compression, shear) and environmental conditions (temperature, humidity) to probe their structural integrity during service life. Recent developments in multiscale simulation, together with increased computational power and improvements in modeling tools, can be used to alleviate this scenario. In this work, high-fidelity simulations of the material behavior at the micro level are used to predict ply properties and ascertain the effect of ply constituents and microstructure on the homogenized ply behavior. This approach relies on the numerical analysis of representative volume elements equipped with physical models of the ply constituents. Its main feature is the ability to provide fast predictions of ply stiffness and strength properties for different environmental conditions of temperature and humidity, in agreement with the experimental results, showing the potential to reduce the time and costs required for material screening and characterization.

F. Pons

Papers

Computational micromechanics of the transverse and shear behavior of unidirectional fiber reinforced polymers including environmental effects

Computational micromechanics of fiber kinking in unidirectional FRP under different environmental conditions