تحلیل و طراحی اتصالات چسبی بین کامپوزیت ها و فلزات

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تست مودالروش اجزای محدودتحلیل سه بعدی تنشمحیط متخلخل اشباعتشریح تعادل شیمیائیبرنامه نویسی ماشینکاریطراحی سطوج پیچیدهPart Designتحلیل سری های زمانیمدار فرمانمدلسازی رفتار غیرالاستیک

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آمار بازدید

بازدید امروز : 28
بازدید دیروز : 80
بازدید کل : 295556

تحلیل و طراحی اتصالات چسبی بین کامپوزیت ها و فلزات

This work is based on the development of numerical tools for the computational analysis of engineering structures that involve adhesion problems, that is interface and interphase problems. The proposed numerical tools are implemented within the framework of non-linear Finite Element Methods (FEM) and are developed so as to be utilized by design engineers and researchers for the design and analysis of adhesively bonded joints and composite structures. Initially, a Progressive Failure Model (PFM) is developed and applied to predict the behaviour of an experimentally tested blade-stiffened panel found in the literature. The developed PFM has been implemented in non-linear finite element analysis procedures under the framework of the commercial software Ansys. Failure initiation and failure propagation as well as the post buckling ultimate attained load have been numerically evaluated. Final failure behaviour of the simulated stiffened panel is due to sudden global failure, as concluded from comparisons between numerical and experimental results being in good agreement.
In the following, particular focus has been given initially in the study of the failure mechanisms that evolve during the pure mode delamination propagation in fiber reinforced composite materials (interface problems) and later in the study of the mixed-mode loading and fracture of adhesively bonded joints (interphase problems). The proposed numerical tools involve novel constitutive relations that describe the aforementioned phenomena and are based on fracture and damage mechanics, in accordance to Cohesive Zone Modeling (CZM) techniques. Initially, a continuum damage constitutive model is presented for the prediction of the inplane failure modes of laminated composite materials. In the following, new cohesive laws are developed for the prediction of delamination initiation and propagation under Mode I and Mode II loading and fracture in fibrous laminated composite materials. Having provided numerical predictions of the failure response of composite materials, the next research activity is focused on providing constitutive relations for the predictions of structural adhesively bonded joints. The proposed constitutive relations, are validated with tests conducted on steel-to-steel and steel-tocomposite adhesive joint geometries that involve flat adherents. Next, a numerical parametric study, that involves axisymmetric adhesive joints (tubular cases), has been conducted, showing the potential of the proposed numerical tool. In conclusion, the present PhD thesis provides separate numerical tools that can be combined for the prediction of the failure response of structures that involve composite materials and adhesive joints.