Research

Current Research

Integrity assessment technique can be based on the notable function of carbon reinforced composites, which electric conductivity. Taking advantage of this property, it is expected that structural health monitoring is performed through the detection of the change in electric resistance or potential. Electric resistance is supposed to be changed by mechanical strain as well as damage accumulation. Work is conducted to define optimum experimental solutions (electrode constitution and spatial disposition, current control, etc), and to develop micromechanical modeling (influence of fiber realignment and corresponding contact changes, fiber breakage) and inverse approaches.
​Micro-scale damage process in thermoplastic composites is studied by capturing the initiation and progression of principal damage modes (transverse crack, and its "migration" into delamination). The first attempt is to study the damage process in unbalanced-unsymmetrical cross-ply laminate at quasi-static rate. The next step is to capture the damage process at high speed. 
​This work aims at developing finite element framework of different length-scales (micro- and mesoscale) in order to study damage mechanism of continuous fiber-reinforced thermoplastic composites. At micro-scale, the unit cell (RVE) is defined rigorously by two-point probability function and Hill-Mandell kinematics. Transverse and shear failure in glass/polypopylene at microscale are simulated. Mesoscale models under in-plane tension and out-of-plane (quasi-static indentation) loads will be developed.
​We aim to investigate how the strength and toughness of uniform adhesive joint depend on different surface preparation techniques. Then, based on the strength and toughness data, precise CZM models for different surface preparation techniques are to be determined.
​Using carbon based nano reinforcements is currently a popular strategy for the synthesis of advanced materials. Generally, the target is to achieve multi-functionality and to fully customize mechanical, electrical and thermal properties of the resulting formulation.
​Improvement in electrical conductivity is necessary to make conductive films, wires and fibers viable candidates in applications such as flexible electrodes, conductive textiles, and fast-response sensors and actuators. Moreover, a dramatic improvement on tensile strength, Young’s modulus on these materials are also important so that they can be use in wearable electronic with a reliable, long cycle life.
We work together with SABIC (Saudi Arabia Basic Industries Corporation) in developing multiscale finite element models for predicting the behavior of continuous fiber reinforced thermoplastic composites. To this end, we fully characterize the thermal and mechanical properties of the thermoplastic polymer (of different formulations), damage mechanisms of thermoplastic composites under in-plane tension and out-of-plane loads (quasi-static indentation and low-velocity impact). We developed in situ technique utilizing fiber Bragg gratings to monitor the processing of thermoplastic composites. The experimental part feeds the model with material data, and validates the developed models.
The academic or industrial usefulness of a multi-scale model depends on the availability of an efficient procedure for the identification of its parameters. This research topic opens the door to quick, versatile techniques by which these parameters can be directly estimated from the structure.
We develop a specific gluing technique, called as morphing method, to couple continuum and nonlocal mechanics models for predicting the material failure. The morphing method couples both models in the level of constitutive parameters in terms of the conservation of strain energy. This capability makes coupling easier to be applied to a complex structure. In addition, this method is easily transferable and nonintrusive for commercial environments.
Composite structures are designed to experience severe circumstances in terms of both mechanical loading and environmental conditions. On the short or long term this will eventually lead to degradations of the structure. Understanding the related mechanisms is fundamental to composite materials. Here, we explore the durability of composite materials, and develop structural health monitoring (SHM) technique utilizing fiber Bragg gratings embedded in the composite system.