摘要:

The behavior of an interface crack between the matrix and the fiber in composite materials subjected to transient heating and cooling is studied. The differences in mechanical and thermal properties of fiber and matrix lead to the failure of the interface between these two constituents. A cylindrical cell of fiber and matrix was analyzed using a cylindrical crack at the interface. The cell was subjected to a transient thermal load, and the corresponding transient strain energy release rate G was calculated using the finite-element method. When the matrix boundary was unconstrained, the largest G occurred during the transient cooling and subsequent heating and was mostly due to shearing of the interface. Constraining the matrix reversed this trend. When the matrix was free, reducing a*m/a*fand E*m/E*fgenerally reduced G, but equality of fiber-matrix thermal expansion coefficients did not always result in the smallest G value. The increase in the fiber volume ratio was detrimental during transient thermal loads but was beneficial for steady-state temperature excursions. The assumption of the free matrix boundary versus the case of a restrained boundary has a considerable effect on the behavior of the fiber matrix interface. Finally, the initial stress free temperature was shown to have a significant effect on the behavior of the fiber-matrix interface crack.

ISSN:0149-5739    

DOI:10.1080/01495739108927047

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The transient temperature and stress fields in a hollow cylinder with an axial surface crack subjected to thermal shock are considered. It is found that the temperature boundary effect exists in a thin layer close to the cooled surface, if the nondimensional Fourier number is not very large. For the third kind of boundary condition ( convection boundary condition) due to thermal shock on the inner surface, the asymptotic solutions of temperature fields are deduced for various values of Biot number. The resulting thermal stresses in the uncracked cylinder, which are necessary for the determination of the stress intensity factor, are solved by quasi-static formulation. By introducing the line spring model considering the arbitrary loads on crack surfaces, the numerical results of the stress intensity factors for a semi-elliptical axial surface crack are obtained as a function of Fourier number and the parametric angle of ellipse for various values of Biot number.

ISSN:0149-5739    

DOI:10.1080/01495739108927048

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The thermal cycling of a layered plate with a flaw, or crack, along an interface is considered. The stress intensities at the crack tips are obtained through the use of a singular integral equation formulation and a Causs-Jacobi numerical scheme. Computations are carried out for a moderately wide range of frequencies and layer thickness-to-crack length ratios, and for various combinations of materials.

ISSN:0149-5739    

DOI:10.1080/01495739108927049

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

We analyze stress effects on multilayered cylinders subjected to a high rate of thermal loading. Thermomechanical coupling is considered, but inertia effect is neglected. Cylindrical symmetry of the structure and of the loading are assumed under plane strain conditions. The solution procedures use the method of the complex frequency response functions in conjunction with the Fourier transform technique. Different coupling parameters and various loading conditions are considered in this study. The results show the coupling term plays an important role for large coupling parameter in thermal shock problem.

ISSN:0149-5739    

DOI:10.1080/01495739108927050

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The theory of generalized thermoelasticity is used to solve the problem related to magnetothermoelastic waves produced by thermal shock in a half-space possessing finite electric conductivity. Eigenvalue approach is applied to obtain solution of the basic equations. Approximate small time solution is obtained by using Laplace transform method.

ISSN:0149-5739    

DOI:10.1080/01495739108927051

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The Lord and Shulman theory of thermoelasticity is used to study the problem of a one-dimensional homogeneous half-space subjected to prescribed values of uniform temperature and strain at its boundary. Asymptotic wavefront expansions are generated by using the ray series method. To obtain numerical results, the region of validity of these asymptotic expansions is extended with the use of Padé approxi-mants. Numerical results obtained for some values of material parameters are displayed graphically. Our results show that the method of Padé-extended ray series expansions provides a powerful tool for obtaining necessary numerical data to test the validity of the Lord and Shulman theory.

ISSN:0149-5739    

DOI:10.1080/01495739108927052

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0149-5739    

DOI:10.1080/01495739108927053

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0149-5739    

DOI:10.1080/01495739108927054

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor