|
| |
|
|
Problems of the crack near the bimaterial interface
Svoboda, Miroslav ; Klusák, Jan (referee) ; Profant, Tomáš (advisor)
Subject of this work is resolving problems of linear crack mechanics, description of stress and deformations in the vicinity of the top of the concentrator with plane elasticity theory in orthotropy materials. First part is engaged in basic relations in crack mechanics. Second part is engaged in numeric-analytic algorithm for determination of stress singularity of crack perpendicular to interface of two materials. Third part is focused on testing algorithm on specific configuration of material and tension of crack in bimaterial interface. In the conclusion, numeric results and impact of mechanic qualities of materials with crack perpendicular to their interface are evaluated.
|
|
|
A study of the stress distribution around the bimaterial notch tip
Hrstka, Miroslav ; Klusák, Jan (referee) ; Profant, Tomáš (advisor)
Presented bachelor’s thesis deals with determination of stress singularity exponent, by which is possible to completely define the stress distribution around the bimaterial notch tip. This task is divided in four parts. The first part concerns with basics of fracture mechanics, concretely linear elastic fracture mechanics of crack and Irwin’s conception of stress intensity factor. The second part deals with generalizing of linear fracture mechanics to notches. In the third part is initiated the numeric-analytical algorithm for computation of stress singularity exponent and determination of strains and stresses of given notch, which is compounded from two orthotropic materials. The last part is created by numerical example, in which the concrete configurations of notches are tested in calculating software.
|
|
|
Problems of the complex potentials of the isotropic elasticity
Padělek, Petr ; Druckmüller, Miloslav (referee) ; Profant, Tomáš (advisor)
The presented Bachelor Thesis investigates the problem of the complex potentials in the isotropic elasticity. The objective of the work is acquiring the components of the stress tensor and the displacement vector which describe the elasticity of continum. This problem is primarily solved on the mathematical level by means of the Airy stress function and the Muschelishvili´s complex potentials. The thesis is supplemented with the necessary theory of the elasticity and finally the concrete solution of the edge dislocation in the infinite domain is demonstrated and compared with the results acquired by FEM method.
|
|
| |
|
|
Comparing FEM with BEM
Zajíček, Vít ; Profant, Tomáš (referee) ; Návrat, Tomáš (advisor)
The thesis explores the possibilities of dealing with problems concerning Elasticity and Strength of materials. In first chapter there is general division of approaches to those problems. Following chapter describes basic principles of Finite Element Method and Boundary Element Method and their use in some simple examples. There is a comparison of those methods as well.
|
|
| |
|
|
On the Problems of LEFM of Composite Materials
Kopp, Dalibor ; Profant, Tomáš (referee) ; Klusák,, Jan (advisor)
The objects of this bachelor thesis is to familiarize oneself with the basics of linear elastic fracture mechanics (LEFM) of homogeneous materials and to specify these problems for composite materials. The work is divided into three parts. The first part is aimed at the basics of LEFM. The second part is concerned with generalization of LEFM. The third part is oriented to the numerical application of the studied problems to notches composed of two orthotropic materials.
|
|
|
Safety factor evaluation for an out-of-plane frame under static loading
Málek, Michal ; Profant, Tomáš (referee) ; Burša, Jiří (advisor)
This bachelor thesis deals with evaluation of safety factor of a space frame when being statically loaded. This examination was demonstrated on a particular example. In order to solve the above mentioned, we exploit the frame symmetry. Unknown parameters were identified from deformation conditions in the point of intersection of the symmetry plane and the frame centreline, where the shift and two turning angles equal zero, and further by means of Maxwell- Mohr variant of Castigliano's theorem for determination of the frame deformation. The basis for calculations of stresses was represented by the theory of combined bar loading, particularly combination of bending and torsion. When examining the frame safety we took into consideration mainly dangerous points possibly occuring through cranks and fixed supports, where stress concentration occurs. The results of analytical solution were verified by numerical calculation in program ANSYS 10.0.
|
|
|
Analysis of the crack initiated from the orthotropic bi-material sharp notch
Profant, T. ; Klusák, Jan ; Kotoul, M.
Under the consideration of the bi-material notch composed of two orthotropic materials the potential direction of the crack initiated from the notch tip is determined from the maximum mean value of the tangential stresses and local minimum of the mean value of the generalized strain energy density factor in both materials. Following the assumption of the same mechanism of the rupture in the case of the crack and the notch, an expression for the critical values of the generalized stress intensity factor can be obtained. The radial and tangential stresses and strain energy density are expressed using the Lekhnitskii-Eshelby-Stroh (LES) formalism for the plane elasticity. The stress singular exponents and corresponding eigenvectors are the solution of the eigenvalue problem leading from the prescribed notch boundary and compatibility conditions. In generally, there is more than one solution of this eigenvalue problem and consequently the generalized stress intensity factors.
|
guest ::
