http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Ahmed, Settet T.,Aguib, Salah,Toufik, Djedid,Noureddine, Chikh,Ahmed, Chellil Techno-Press 2019 Coupled systems mechanics Vol.8 No.6
The present work is the study of mechanical behavior due to variation of the geometrical parameters in the core of the sandwich honeycomb panel. This study has allowed us to increase or decrease the strains and stresses of the panel, in changing the angle of alveolus, as explained and described below. In taking into consideration the results obtained previously to improve the mechanical properties and increase the adhesion of different parts of the panel, without changing the adhesive, we have conceived two new models, in increasing the contact surfaces in boundary of each part of the panel and giving a conical hexagonal shape in his corp.
Massinissa Grabi,Ahmed Chellil,Mohamed Habibi,Luc Laperriere 한국섬유공학회 2022 Fibers and polymers Vol.23 No.10
Improving the mechanical properties and reduced damage of natural fiber-reinforced composites can contribute totheir increased use in various fields. In this paper, an experimental study describes the effect of alkaline treatment of twodifferent concentrations of 2 % and 5 % NaOH for one hour on the mechanical performance and damage of luffa fibercomposites. Three different composites reinforced with treated and untreated luffa fibers were developed using the resintransfer molding (RTM) process. The specimens were coupled with acoustic emission during tensile tests, to monitor andevaluate damage mechanisms. The tensile test results showed that the alkaline treatment of 5 % improved tensile strength,which reached 81.08±1.48 MPa. However, the 2 % treatment improved Young's modulus with 8.94±0.5 GPa. In comparison,T2 % and T5 % composites provided the best results for mechanical properties compared to NT composites. Four classes ofdamage mechanisms have been identified using the K-means clustering method, including matrix cracking, fiber pull-out,delamination, and fiber breakage. The cumulated energy and hits of the 5 % treated composite was lower than the untreatedand 2 % treated, which means less damage to the T5 % specimen. Scanning electron microscopy (SEM) pictures of thetensile fractured surfaces of luffa fiber composites treated with 5 % NaOH, revealed good adhesion between the fibers andthe matrix. The AE results are convincing, and they were confirmed by SEM pictures of the specimens' fractured faces,which revealed the main causes of material failure, So, based on the AE results and mechanical properties, T5 % composite ispreferable.
Dynamic prediction fatigue life of composite wind turbine blade
Samir Lecheb,Abdelkader Nour,Ahmed Chellil,Hamza Mechakra,Hicham Ghanem,Hocine Kebir 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.3
In this paper we are particularly focusing on the dynamic crack fatigue life of a 25 m length wind turbine blade. The blade consists of composite materiel (glass/epoxy). This work consisted initially to make a theoretical study, the turbine blade is modeled as a Timoshenko rotating beam and the analytical formulation is obtained. After applying boundary condition and loads, we have studied the stress, strain and displacement in order to determine the critical zone, also show the six first modes shapes to the wind turbine blade. Secondly was addressed to study the crack initiation in critical zone which based to finite element to give the results, then follow the evolution of the displacement, strain, stress and first six naturals frequencies a function as crack growth. In the experimental part the laminate plate specimen with two layers is tested under cyclic load in fully reversible tensile at ratio test (R = 0), the fast fracture occur phenomenon and the fatigue life are presented, the fatigue testing exerted in INSTRON 8801 machine. Finally which allows the knowledge their effect on the fatigue life, this residual change of dynamic behavior parameters can be used to predicted a crack size and diagnostic of blade.
Abdelhafd Bensalem,Abdelhakim Daoui,Abderrahmane Cheriet,Samir Lecheb,Ahmed Chellil,Hocine Kebir,Linda Aissani 한국섬유공학회 2023 Fibers and polymers Vol.24 No.11
The Hashin’s criteria are useful in composite structural applications because of their simple concept and their theoretical results are relatively close to that got in the experimental parts. In the present study, in the present study, the failure of the composite laminates under static loading have been developed predicted using Hashin’s Criterion. Nonhomogeneous stresses within a structure may induce a complicated failure scenario whereby one ply at a point can initiate failure and can affect also other plies at the same point or the same ply in different neighboring points. With neglecting the possibility of interlaminar failure, only in-plane loads are considered in this state. The results showed that the failure analysis was proposed to simulate the nonlinear laminate behavior and progressive damage of selected laminates under to their ultimate strength. In our approach, the finite element analysis is performed using MATLAB software to study the effect of tensile and compressive loading on the failure of epoxy resin laminate AS4/3501-6.