Publications by Roohollah Sarfaraz Khabbaz

Fracture mechanics-based progressive damage modelling of adhesively bonded fibre-reinforced polymer joints

Thomas Keller, Anastasios Vassilopoulos, Moslem Shahverdi, Roohollah Sarfaraz Khabbaz, Aida Cameselle Molares

A quasi-static progressive damage model for prediction of the fracture behaviour and strength of adhesively bonded fibre-reinforced polymer joints is introduced in this paper. The model is based on the development of a mixed-mode failure criterion as a fun ...

Wiley2017

An experimental-numerical investigation of hydrothermal response in adhesively bonded composite structures

John Botsis, Véronique Michaud, Hans Georg Limberger, Roohollah Sarfaraz Khabbaz, Georgios Violakis, Luis Pablo Canal Casado

Water absorption and thermal response of adhesive composite joints were investigated by measurements and numerical simulations. Water diffusivity, saturation, swelling, and thermal expansion of the constituent materials and the joint were obtained from gra ...

Elsevier2015

MODELING THE PROGRESSIVE DAMAGE OF ADHESIVELY BONDED JOINTS

Thomas Keller, Anastasios Vassilopoulos, Moslem Shahverdi, Roohollah Sarfaraz Khabbaz

A quasi-static progressive damage model based on the fracture mechanics approach was developed for adhesively-bonded pultruded glass fiber-reinforced polymer (GFRP) joints. The model comprises the implementation in a numerical algorithm of a mixed-mode fra ...

2014

Monitoring strain gradients in adhesive composite joints by embedded fiber Bragg grating sensors

John Botsis, Véronique Michaud, Hans Georg Limberger, Roohollah Sarfaraz Khabbaz, Georgios Violakis, Luis Pablo Canal Casado

The adhesive bonding of composite materials can be applied to assemble light-weight structures for aeronautical applications. However, the application of adhesive bonds in primary load-bearing structures is limited by the lack of adequate techniques to mon ...

Elsevier2014

Modeling the constant amplitude fatigue behavior of adhesively bonded pultruded GFRP joints

Thomas Keller, Anastasios Vassilopoulos, Roohollah Sarfaraz Khabbaz

The constant amplitude fatigue behavior of adhesively bonded pultruded glass fiber reinforced polymer double-lap joints were modeled by a number of conceptually different phenomenological SN (cyclic stress vs. number of cycle) formulations. An extended dat ...

Brill Academic Publishers2013

Variable amplitude fatigue of adhesively-bonded pultruded GFRP joints

Thomas Keller, Anastasios Vassilopoulos, Roohollah Sarfaraz Khabbaz

The fatigue behavior of adhesively-bonded pultruded GFRP joints subjected to variable amplitude loading patterns was experimentally investigated. The failure mode of the examined joints was found to be similar to that under constant amplitude loading. The ...

Elsevier Sci Ltd2013

Block loading fatigue of adhesively bonded pultruded GFRP joints

Thomas Keller, Anastasios Vassilopoulos, Roohollah Sarfaraz Khabbaz

The effect of loading sequence on the fatigue behavior of adhesively-bonded pultruded GFRP double-lap joints was experimentally investigated by applying different tensile and compressive block loading patterns. The observed failure modes were consistent wi ...

2013

Fatigue Life Prediction of Adhesively-Bonded Fiber-Reinforced Polymer Structural Joints under Spectrum Loading Patterns

Roohollah Sarfaraz Khabbaz

New load-bearing structures made of fiber-reinforced polymer (FRP) composites comprise adhesively-bonded joints, which are components vulnerable to fatigue failure. These structural components are frequently subjected to complex cyclic loading histories ...

EPFL2012

A hybrid S-N formulation for fatigue life modeling of composite materials and structures

Thomas Keller, Anastasios Vassilopoulos, Roohollah Sarfaraz Khabbaz

A semi-empirical S-N formulation for the modeling of the constant amplitude fatigue behavior of composite materials and structures is introduced in this paper. The new S-N formulation is based on the commonly used exponential and power law fatigue models. ...

Elsevier2012

Experimental investigation and modeling of mean load effect on fatigue behavior of adhesively-bonded pultruded GFRP joints

Thomas Keller, Anastasios Vassilopoulos, Roohollah Sarfaraz Khabbaz

The effect of mean load on the fatigue behavior of adhesively-bonded pultruded GFRP double-lap joints under constant amplitude loading was experimentally investigated. The joints were examined under nine different stress ratios (R) representing pure tensio ...

Elsevier2012