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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Mechanics of Advanced Composite Structures
- نوع مقاله: Journal Article
- کلمات کلیدی: Impact properties,Glass/epoxy composites,Fiber metal laminates (FMLs),Hygrothermal aging,Flexural properties
- چکیده:
- چکیده انگلیسی: In this article, the effect of hygrothermal aging on mechanical properties of fiber metal laminates (FMLs) and E-glass/epoxy (GE) composites is investigated. First, FML and GE specimens were built using wet lay-up technique under vacuum pressure. Hygrothermal aging simulation was then carried out on both specimen types in distilled water at a constant temperature of 90 °C for 5 weeks. The resulting behavior of degradation for both types of specimens caused by hygrothermal aging was evaluated by bending and Charpy impact testing. As expected, because of the protective role of aluminum layers, FML specimens showed remarkably lower water absorption after hygrothermal aging compared to the glass/epoxy composites. Experimental results also revealed that the flexural properties of both the FML and GE laminates were affected by the hygrothermal aging, whereas a lower level of deterioration in impact strength was found.
- انتشار مقاله: 02-08-1395
- نویسندگان: Moslem Najafi,Reza Ansari,Abolfazl Darvizeh
- مشاهده
- جایگاه : پژوهشی
- مجله: Mechanics of Advanced Composite Structures
- نوع مقاله: Journal Article
- کلمات کلیدی: Impact properties,Glass/epoxy composites,Fiber metal laminates (FMLs),Flexural properties,Iso-thermal aging
- چکیده:
- چکیده انگلیسی: The aim of this study is to investigate effects of isothermal aging on mechanical properties of fiber metal laminates (FMLs) and glass/epoxy composites. For this purpose, both materials were fabricated using the wet lay-up manufacturing technique under vacuum pressure. Both the glass/epoxy composites and the FML specimens were then subjected to isothermal aging (130°C, dried air) for up to 5 weeks. After the isothermal aging, the specimens’ weight loss, caused by thermo-oxidative conditioning, was evaluated. Bending and Charpy impact tests were conducted on both the unaged and aged specimens to examine the isothermal conditioning’s effect on the mechanical properties of studied materials. Experimental results revealed that isothermal aging severely affected impact strength in the form of embrittlement and reduced ductility. However, no significant reduction was found in the flexural stiffness of isothermally aged FML and glass/epoxy specimens.
- انتشار مقاله: 02-08-1395
- نویسندگان: Moslem Najafi,Reza Ansari,Abolfazl Darvizeh
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Simulation and Analysis of Novel Technologies in Mechanical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Discontinuity,Beam,Strong and Weak Forms,Euler-Bernoulli and Timoshenko Theories
- چکیده:
- چکیده انگلیسی: In this paper, a discontinuity in beams whose intensity is adjusted by the spring stiffness factor is modeled using a torsional spring. Adapting two analyses in strong and weak forms for discontinuous beams, the improved governing differential equations and the modified stiffness matrix are derived respectively. In the strong form, two different solution methods have been presented to make an analogy between the formulation of the Euler-Bernoulli and Timoshenko theories that indicates the influence of the shear deformation in discontinuous beams. The flexural stiffness of discontinuous beams is corrected by using the Dirac’s delta function. In the weak form, the reduced stiffness matrix is derived from the strain energy equation established by the continuity, kinematics and constitutive equations. The linearity assumption of the geometry and material is considered to construct the kinematics and constitutive equations respectively. The continuity conditions mathematically connect two divided parts of the Euler-Bernoulli beam for which an improved Hermitian shape function is employed to interpolate displacement field. An application shows the comparison and validation of the results of the strong and weak forms, and also the quasi-static behavior of discontinuous beams.
- انتشار مقاله: 05-08-1394
- نویسندگان: Mostafa Mastanabadi,Ali Alijani,Abolfazl Darvizeh,Fatemeh Mottaghian
- مشاهده