Search for dissertations about: "Strain rate sensitivity"

Showing result 1 - 5 of 34 swedish dissertations containing the words Strain rate sensitivity.

2. 1. The Plastic Flow Behaviour of Aluminium Alloys Exhibiting Dynamic Strain Ageing

   Author : Magnus Hörnqvist Colliander; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Al-Zn-Mg; Dynamic strain ageing; Strain rate sensitivity; Portevin-Le Chatelier effect; Temperature sensitivity; Thermal activation;

   Abstract : The phenomenon known as dynamic strain ageing, abbreviated DSA, has been known since the beginning of last century. It was first discovered as serrations in the load-elongation curve obtained upon deforming specimens of certain alloys in tension. This phenomenon became known as the Portevin-Le Chatelier (PLC) effect. READ MORE

4. 2. Numerical Modeling of Plasticity in FCC Crystalline Materials Using Discrete Dislocation Dynamics

   Author : Arash Hosseinzadeh Delandar; Pavel Korzhavyi; Rolf Sandström; Mikko Alava; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Dislocations; crystal plasticity; discrete dislocation dynamics; Cu single crystal; high strain rate deformation; strain rate sensitivity; plastic anisotropy; slip band formation; Teknisk materialvetenskap; Materials Science and Engineering;

   Abstract : Plasticity in crystalline solids is controlled by the microscopic line defects known as “dislocations”. Decisive role of dislocations in crystal plasticity in addition to fundamentals of plastic deformation are presented in the current thesis work. READ MORE

5. 3. Monotonic and Cyclic Plastic Deformation of High-Strength Aluminium Alloys

   Author : Magnus Hörnqvist Colliander; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strain rate effects; Heat treatment; Dynamic strain ageing; Precipitation hardening; Low cycle fatigue; AA7030; Plastic deformation; Temperature effects; EN AW-7030; Al-Zn-Mg; Strain hardening; Mechanical properties; Dynamic precipitation.;

   Abstract : Dynamic strain ageing (DSA) and dynamic precipitation (DP) are two, closely interrelated, phenomena arising from the dynamic interaction between mobile solute atoms and dislocations. The occurrence of DSA and DP is confined to specific ranges of strain rate and temperature, and aluminium alloys are generally prone to experience DSA and DP already at ambient temperatures and conventional strainrates. READ MORE

6. 4. Topology optimization of non-linear, dissipative structures and materials

   Author : Niklas Ivarsson; Hållfasthetslära; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Topology optimization; Stiffness optimization; Finite strain; Rate-dependent plasticity; Discrete adjoint sensitivity analysis;

   Abstract : Topology optimization is a mathematical tool for finding optimal distributions of material phases within a design domain. It is commonly used in early design stages to generate conceptual structural layouts. Ultimately, designs generated by topology optimization consist of distinct material phases with enhanced performance. READ MORE

7. 5. On cyclic accumulation models for degradation of railway foundations

   Author : Hossein Tahershamsi; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Natural soft clay; Global Sensitivity Analysis; Sobol method; Experimental design; Rate-dependent models; Cyclic accumulation models; Cyclic degradation; Uncertainty analysis;

   Abstract : The degradation of railway foundations due to the repeated loading of traffic induces maintenance and safety obligations for the track operator. One major contributor to track degradation is the accelerated settlement rates in soft soils below the track that lead to alignment issues, especially at stiffness transitions. READ MORE