Roohollah Sarfaraz
Shahid Beheshti University
Composite numberUltimate tensile strengthFatigue limitFinite element methodComposite materialEpoxyAbsorption of waterCompression (physics)AmplitudeMaterials scienceTension (physics)Constant (mathematics)Fatigue testingCompressive loadStrain energy release rateThermal diffusivityFiber Bragg gratingFracture (geology)Thermal expansionPultrusionFracture mechanicsCyclic stressFailure mode and effects analysisStructural engineeringAdhesiveDynamic mechanical analysisFibre-reinforced plasticBendingStress (mechanics)Gravimetric analysis
20Publications
8H-index
179Citations
Publications 20
Newest
Abstract The damage mechanism in a composite plate with an edge notch influenced by water freezing and subjected to bending loading is investigated using Scanning Electron Microscopy images. The microstructure of the composite plate around the notch tip induced by freeze-thaw cycles is compared to dry specimens and showed a change in shape of the notch in micro-scale as well as introducing surface minor damage after conditioning. Moreover, the fracture surface of specimens, conditioned for 10, 2...
Source
#1Mohsen Malmorad (Shahid Beheshti University)
#2Khosrow Rahmani (Shahid Beheshti University)H-Index: 1
Last. Roohollah Sarfaraz (Shahid Beheshti University)H-Index: 8
view all 3 authors...
Abstract The flexural behavior of hybrid composite rods used in high capacity low sag overhead conductors at elevated temperatures is experimentally investigated. Dynamic mechanical analysis (DMA) is carried out on pultruded carbon/glass/epoxy specimens, followed by three-point bending experiments at different elevated temperatures. The failure mechanisms are examined by using macro/micro images taken from the failed specimens. The results show that flexural properties such as strength and modul...
Source
#1M. Javanmard (Shahid Beheshti University)
#2Roohollah Sarfaraz (Shahid Beheshti University)H-Index: 8
Last. S.M. Yadavar Nikravesh (Shahid Beheshti University)
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Abstract Sonic soot blower, utilizing an oscillating diaphragm, generates acoustic waves for cleaning of equipment such as boiler and furnace to increase their efficiency. Based on earlier research by NRI (Niroo Research Institute), one of the main reasons disrupting the regular function of sonic soot blower is the failure of the diaphragm. The failure of circular Ti-6Al-4V sheets employed as the diaphragms is investigated by using SEM images. Based on these images, fatigue failure is found in t...
Source
#1Mohammad Abedi (Shahid Beheshti University)H-Index: 2
#2Seyyed‐Ebrahim Moussavi‐Torshizi (Shahid Beheshti University)H-Index: 1
Last. Roohollah Sarfaraz (Shahid Beheshti University)H-Index: 8
view all 3 authors...
2 CitationsSource
#1Aida Cameselle-Molares (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 4
#2Roohollah Sarfaraz (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 8
Last. Anastasios P. Vassilopoulos (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 28
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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 function of a master R-curve derived from the experimental results obtained from standard fracture mechanics joints. Consequently, the developed failure criterion is crack-length and mode-mixity dependent, and it takes into account the contributio...
6 CitationsSource
#1Roohollah Sarfaraz (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 8
#2Luis P. Canal (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 11
Last. Hans G. Limberger (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 24
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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 gravimetric experiments and strain measurements using embedded fiber Bragg grating (FBG) sensors. The mechanical response of these materials at different temperatures and water content was characterized by dynamic mechanical analysis. Thermal load...
3 CitationsSource
#1Roohollah Sarfaraz (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 8
Load-bearing structural components such as adhesively-bonded joints are frequently subjected to complex cyclic loading histories during their service life. In this chapter, the effects of loading parameters existing in these loading histories are discussed. Experimental investigations show that these parameters, namely mean stress, creep–fatigue interaction, load sequence, and load transition, significantly influence the fatigue behavior of adhesively-bonded composite joints. Following the discu...
Source
#1Roohollah SarfarazH-Index: 8
#2Luis P. CanalH-Index: 11
Last. Hans G. LimbergerH-Index: 24
view all 6 authors...
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 gravimetric experiments and strain measurements using embedded fiber Bragg grating (FBG) sensors. The mechanical response of these materials at different temperatures and water content was characterized by dynamic mechanical analysis. Thermal load...
#1Luis P. Canal (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 11
#2Roohollah Sarfaraz (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 8
Last. Hans G. Limberger (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 24
view all 6 authors...
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 monitor the quality of the joint during service. This work evaluates the feasibility of using Fiber Bragg Grating (FBG) arrays to monitor the distribution of strains developed along the bonded region in single lap shear specimens. Three different ...
33 CitationsSource
#2Roohollah SarfarazH-Index: 8
Last. Thomas KellerH-Index: 45
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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 fracture failure criterion, experimentally developed using data acquired under pure Mode I and II and mixed-Mode I/II loading conditions. The bridging effect, as exhibited mainly by the R-curve behavior of the examined joints, was taken into accou...