haku: @supervisor Tuhkuri, Jukka / yhteensä: 83
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| Tekijä: | Mousavi, Seyedvahid |
| Työn nimi: | Prevention of localisation problem due to damage by a gradient theory |
| Julkaisutyyppi: | Diplomityö |
| Julkaisuvuosi: | 2015 |
| Sivut: | 128 s. + liitt. 16 Kieli: eng |
| Koulu/Laitos/Osasto: | Insinööritieteiden korkeakoulu |
| Oppiaine: | Mechanical Engineering (IA3027) |
| Valvoja: | Tuhkuri, Jukka |
| Ohjaaja: | Santaoja, Kari |
| Elektroninen julkaisu: | http://urn.fi/URN:NBN:fi:aalto-201505283012 |
| Sijainti: | P1 Ark Aalto 4311 | Arkisto |
| Avainsanat: | continuum mechanics damage localisation gradient theory |
| Tiivistelmä (eng): | The microstructure of a typical material contains a large number of microdefects which are small and distributed throughout most of the volume. The concept of damage is introduced to quantify the cumulative effect of these microdefects. As damage develops, its distribution becomes anisotropic and hence, the damage has to be characterized by more complicated definitions. Critical development of damage leads to strain softening, which is the beginning of the structural failure by inducing localisation of damage. The primary aim of this work is to study the problems that localisation of the damage causes for finite element solutions, and find the remedies that regularize these problems according to nonlocal theories, with the objective to introduce a novel material model with nonlocal formulation of gradient damage that is capable of modelling softening behaviour while preventing the problem due to localisation of damage. A literature review on damage mechanics including fundamental and advanced subjects which comprises the foundation of the research topic, together with the theoretical and finite element implementation of the prepared material model is presented. The model is verified by two computing test cases. First results for ductile damage show that the mechanical behaviour of the specimen does not depend on the mesh and allows to regularize the problem within small strain framework. Mesh dependency is witnessed for the second results implying the incapability of the current formulation of the material model to incorporate brittle damage. |
| ED: | 2015-06-21 |
INSSI tietueen numero: 51491
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