Finite element analysis of edge cracked bimaterial systems under thermal loading /
In several engineering applications, the multi-layered structural components of dissimilar materials with various thermo mechanical properties are used to protect the base metal from damages which occur due to thermal effect. For instant, thermal barrier coating is used in jet engines which is made...
Saved in:
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur :
Kulliyyah of Engineering,
2019
|
| Subjects: | |
| Online Access: | Click here to view 1st 24 pages of the thesis. Members can view fulltext at the specified PCs in the library. |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | In several engineering applications, the multi-layered structural components of dissimilar materials with various thermo mechanical properties are used to protect the base metal from damages which occur due to thermal effect. For instant, thermal barrier coating is used in jet engines which is made up of ceramic, in pressure vessels and pipes, stainless steel cladding is used and in microelectronic devices, variety of bonded structures are used. One of the important modes of failure in these components were due to the presence of cracks or preexisting flaws aroused by thermal loading. In this thesis, crack problem for bi-material systems namely a stainless steel layer welded on ferritic steel and a ceramic layer coating on ferritic steel subjected to transient thermal loading was considered. Temperature distribution, thermal stress distribution and stress intensity factor (SIF) had been determined using finite element analysis for two different bi-material systems containing edge crack with different crack lengths. It was well-recognized that, when a bi-material system's crack surface is heated, negative stresses form closely by the heating surface, forcing the crack surfaces together over a certain cusp-shaped contact length. It is also notorious that, for a cooled bi-material surface, tensile stresses are formed close to the cooling surface which will tend to enlarge the crack. The uniqueness of the problem is that this is the pure simulation work of crack perpendicular to the interface. The values of temperature distribution, thermal stress distribution and SIF were normalized and compared with the analytical results of thermal cooling and thermal heating available in the literature. The influence of the meshing, the element on the crack tip and near the insulated surface were precisely identified. The temperature distribution and thermal stress distribution were normalized and plotted versus normalized coordinates and SIFs were plotted against normalized time for different thickness ratios. The percentage error between analytical and finite element results of thermal stress at the crack face, at the interface and at the end of the plate were found to be 2.7%, 12% and 4%, respectively. |
|---|---|
| Physical Description: | xvi, 93 leaves : colour illustrations ; 30cm. |
| Bibliography: | Includes bibliographical references (leaves 78-80). |