• 제목/요약/키워드: temperature dependent material properties

검색결과 359건 처리시간 0.023초

Effects of temperature dependent material properties on mixed mode crack tip parameters of functionally graded materials

  • Rajabi, Mohammad;Soltani, Nasser;Eshraghi, Iman
    • Structural Engineering and Mechanics
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    • 제58권2호
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    • pp.217-230
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    • 2016
  • Effects of temperature dependent material properties on mixed mode fracture parameters of functionally graded materials subjected to thermal loading are investigated. A domain form of the $J_k$-integral method including temperature-dependent material properties and its numerical implementation using finite element analysis is presented. Temperature and displacement fields are calculated using finite element analysis and are used to compute mixed mode stress intensity factors using the $J_k$-integral. Numerical results indicate that temperature-dependency of material properties has considerable effect on the mixed-mode stress intensity factors of cracked functionally graded structures.

Thermal post-buckling analysis of functionally graded beams with temperature-dependent physical properties

  • Kocaturk, Turgut;Akbas, Seref Doguscan
    • Steel and Composite Structures
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    • 제15권5호
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    • pp.481-505
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    • 2013
  • This paper focuses on thermal post-buckling analysis of functionally graded beams with temperature dependent physical properties by using the total Lagrangian Timoshenko beam element approximation. Material properties of the beam change in the thickness direction according to a power-law function. The beam is clamped at both ends. In the case of beams with immovable ends, temperature rise causes compressible forces and therefore buckling and post-buckling phenomena occurs. It is known that post-buckling problems are geometrically nonlinear problems. Also, the material properties (Young's modulus, coefficient of thermal expansion, yield stress) are temperature dependent: That is the coefficients of the governing equations are not constant in this study. This situation suggests the physical nonlinearity of the problem. Hence, the considered problem is both geometrically and physically nonlinear. The considered highly non-linear problem is solved considering full geometric non-linearity by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. In this study, the differences between temperature dependent and independent physical properties are investigated for functionally graded beams in detail in post-buckling case. With the effects of material gradient property and thermal load, the relationships between deflections, critical buckling temperature and maximum stresses of the beams are illustrated in detail in post-buckling case.

Impact of the homogenization models on the thermoelastic response of FG plates on variable elastic foundation

  • Rachedi, Mohamed Ali;Benyoucef, Samir;Bouhadra, Abdelhakim;Bouiadjra, Rabbab Bachir;Sekkal, Mohamed;Benachour, Abdelkader
    • Geomechanics and Engineering
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    • 제22권1호
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    • pp.65-80
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    • 2020
  • This paper presents a theoretical investigation on the response of the thermo-mechanical bending of FG plate on variable elastic foundation. A quasi-3D higher shear deformation theory is used that contains undetermined integral forms and involves only four unknowns to derive. The FG plates are supposed simply supported with temperature-dependent material properties and subjected to nonlinear temperature rise. Various homogenization models are used to estimate the effective material properties such as temperature-dependent thermoelastic properties. Equations of motion are derived from the principle of virtual displacements and Navier's solution is used to solve the problem of simply supported plates. Numerical results for deflections and stresses of FG plate with temperature-dependent material properties are investigated. It can be concluded that the proposed theory is accurate and simple in solving the thermoelastic bending behavior of FG thick plates.

Wave propagation of FGM plate via new integral inverse cotangential shear model with temperature-dependent material properties

  • Mokhtar Ellali;Mokhtar Bouazza;Ashraf M. Zenkour
    • Geomechanics and Engineering
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    • 제33권5호
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    • pp.427-437
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    • 2023
  • The objective of this work is to study the wave propagation of an FGM plate via a new integral inverse shear model with temperature-dependent material properties. In this contribution, a new model based on a high-order theory field of displacement is included by introducing indeterminate integral variables and inverse co-tangential functions for the presentation of shear stress. The temperature-dependent properties of the FGM plate are assumed mixture of metal and ceramic, and its properties change by the power functions of the thickness of the plate. By applying Hamilton's principle, general formulas of wave propagation were obtained to plot the phase velocity curves and wave modes of the FGM plate with simply supported edges. The effects of the temperature and volume fraction by distributions on wave propagation of the FGM plate are investigated in detail. The results of the dispersion and the phase velocity curves of the propagation wave in the functionally graded plate are compared with previous research.

Buckling analysis of nanoplate-type temperature-dependent heterogeneous materials

  • Karami, Behrouz;Karami, Sara
    • Advances in nano research
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    • 제7권1호
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    • pp.51-61
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    • 2019
  • This paper develops a four-unknown refined plate theory and the Galerkin method to investigate the size-dependent stability behavior of functionally graded material (FGM) under the thermal environment and the FGM having temperature-dependent material properties. In the current study two scale coefficients are considered to examine buckling behavior much accurately. Reuss micromechanical scheme is utilized to estimate the material properties of inhomogeneous nano-size plates. Governing differential equations, classical and non-classical boundary conditions are obtained by utilizing Hamiltonian principles. The results showed the high importance of considering temperature-dependent material properties for buckling analysis. Different influencing parametric on the buckling is studied which may help in design guidelines of such complex structures.

차량용 브레이크 코너 모듈에서 마찰재의 온도와 압력에 따른 물성치 변화를 고려한 스퀼 소음 해석 연구 (A Study on Squeal Noise Simulation considering the Friction Material Property Changes according to Temperature and Pressure in an Automotive Brake Corner Module)

  • 조호준;김정태;채호중
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2012년도 추계학술대회 논문집
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    • pp.546-552
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    • 2012
  • This paper is a study on squeal noise simulation under the consideration of temperature and pressure dependent material properties of friction material. For this, data of pressure and temperature dependent material properties of lining is achieved by using lining data base and exponential curve fit. Complex eigenvalue analysis is performed for predicting squeal noise frequency and instability and chassis dynamo test is performed for achieving squeal noise frequency, sound pressure level, occurrence temperature & pressure. Initial multi models are composed for considering complex interface conditions such as pad ear-clip, piston-housing and guide pin-torque member. The simulation result of base models is compared with the test result. Squeal noise simulation under the consideration of temperature and pressure dependent material properties of friction material is performed and analyzed using multi models. And additional condition is disc material property variation. Entire simulation conditions are combined and analyzed. Finally, this paper proposes direction of the warm squeal noise model.

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DEVELOPMENT OF GREEN'S FUNCTION APPROACH CONSIDERING TEMPERATURE-DEPENDENT MATERIAL PROPERTIES AND ITS APPLICATION

  • Ko, Han-Ok;Jhung, Myung Jo;Choi, Jae-Boong
    • Nuclear Engineering and Technology
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    • 제46권1호
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    • pp.101-108
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    • 2014
  • About 40% of reactors in the world are being operated beyond design life or are approaching the end of their life cycle. During long-term operation, various degradation mechanisms occur. Fatigue caused by alternating operational stresses in terms of temperature or pressure change is an important damage mechanism in continued operation of nuclear power plants. To monitor the fatigue damage of components, Fatigue Monitoring System (FMS) has been installed. Most FMSs have used Green's Function Approach (GFA) to calculate the thermal stresses rapidly. However, if temperature-dependent material properties are used in a detailed FEM, there is a maximum peak stress discrepancy between a conventional GFA and a detailed FEM because constant material properties are used in a conventional method. Therefore, if a conventional method is used in the fatigue evaluation, thermal stresses for various operating cycles may be calculated incorrectly and it may lead to an unreliable estimation. So, in this paper, the modified GFA which can consider temperature-dependent material properties is proposed by using an artificial neural network and weight factor. To verify the proposed method, thermal stresses by the new method are compared with those by FEM. Finally, pros and cons of the new method as well as technical findings from the assessment are discussed.

온도 의존적 재료물성치를 고려한 개선된 그린함수 기반 열응력 계산 (Thermal Stress Calculations Using Enhanced Green's Function Considering Temperature-dependent Material Properties)

  • 한태송;허남수;전현익;하승우;조선영
    • 한국생산제조학회지
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    • 제24권5호
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    • pp.535-540
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    • 2015
  • We propose an enhanced Green's function approach to predict thermal stresses by considering temperature-dependent material properties. We introduce three correction factors for the maximum stress, the time taken to reach maximum stress, and the time required to attain steady state based on the Green's function results for each temperature. The proposed approach considers temperature-dependent material properties using correction factors, which are defined as polynomial expressions with respect to temperatures based on Green's functions, that we obtain from finite-element (FE) analyses at each temperature. We verify the proposed approach by performing detailed FE analyses on thermal transients. The Green's functions predicted by the proposed approach are in good agreement with those obtained from FE analyses for all temperatures. Moreover, the thermal stresses predicted using the proposed approach are also in good agreement with the FE results, and the proposed approach provides better predictions than the conventional Green's function approach using constant, time-independent material properties.

Assessing the effect of temperature-dependent properties on the dynamic behavior of FG porous beams rested on variable elastic foundation

  • Abdeljalil Meksi;Mohamed Sekkal;Rabbab Bachir Bouiadjra;Samir Benyoucef;Abdelouahed Tounsi
    • Structural Engineering and Mechanics
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    • 제85권6호
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    • pp.717-728
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    • 2023
  • The effect of temperature dependent material properties on the free vibration of FG porous beams is investigated in the present paper. A quasi-3D shear deformation solution is used involves only three unknown function. The mechanical properties which are considered to be temperature-dependent as well as the porosity distributions are assumed to gradually change along the thickness direction according to defined law. The beam is supposed to be simply supported and lying on variable elastic foundation. The differential equation system governing the free vibration behavior of porous beams is derived based on the Hamilton principle. Navier's method for simply supported systems is then used to determine and compute the frequencies of FG porous beam. The results of the present formulation are validated by comparing with those available literatures. Finally, the effects of several parameters such as porosity distribution and the parameters of variable elastic foundation on the free vibration behavior of temperature-dependent FG beams are presented and discussed in detail.

Residual stress in an elastoplastic annular disc interacting with an elastic inclusion

  • Zarandi, Somayeh Bagherinejad;Lai, Hsiang-Wei;Wang, Yun-Che;Aizikovich, Sergey M.
    • Coupled systems mechanics
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    • 제8권3호
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    • pp.273-287
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    • 2019
  • Elastoplastic analysis of an annular disc, being fully constrained on its outer rim and interacting with a purely elastic inclusion perfectly bonded with its inner rim, is conducted to study its plastic deformation and residual stress under thermal cycles. The system is termed the composite disc. Quasi-static plane-strain deformation is assumed, and the von Mises yield criterion with or without the Ludwik hardening rule is adopted in our finite element calculations. Effects of multiple material properties simultaneously being temperature dependent on the plastic behavior of the composite disc are considered. Residual stress is analyzed from a complete loading and unloading cycle. Results are discussed for various inclusion radii. It is found that when temperature dependent material properties are considered, the maximum residual stress may be greater than the maximum stress inside the disc at the temperature-loaded state due to lower temperature having larger yield stress. Temperature independent material properties overestimate stresses inside materials, as well as the elastic irreversible temperature and plastic collapse temperature.