Search for dissertations about: "micro-crack"

Showing result 1 - 5 of 7 swedish dissertations containing the word micro-crack.

2. 1. Micro-crack initiation and propagation in fiber reinforced composites

   Author : Andrejs Pupurs; Stephen L. Ogin; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Polymera konstruktionsmaterial; Polymeric Composite Materials;

   Abstract : Predicting micro-damage initiation and evolution is one of the key challenges for safe design of fiber reinforced polymer composites. Micro-scale damage such as, for example, single fiber break may be unnoticeable and negligible during the initial service life of composite, however, with many loading and unloading cycles this initially micro-scale damage may propagate forming macroscopic scale cracks that can significantly reduce the service lifetime or even lead to unforeseen catastrophic failure of the composite structure. READ MORE

4. 2. On the deformation behavior and cracking of ductile iron; effect of microstructure

   Author : Keivan Amiri Kasvayee; Anders E.W. Jarfors; Jens Bergström; Jönköping University; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spherical graphite iron; component casting; high silicon ductile iron; digital image correlation DIC ; in-situ tensile testing; in-situ cyclic testing; DIC pattern generation; pit etching; micro-scale deformation; micro-crack; finite element analysis FEA ; focused ion beam FIB milling; segjärn; komponentgjutning; högkisellegerat segjärn; digital image correlation DIC ; insitu dragprovning; in-situ cyklisk provning; DIC-mönstergenerering; grop-etsning; mikroskalig deformation; mikrosprickor; finite element analys FEA ; fokuserad jonstråle FIB avverkning;

   Abstract : This thesis focuses on the effect of microstructural variation on the mechanical properties and deformation behavior of ductile iron. To research and determine these effects, two grades of ductile iron, (i) GJS-500-7 and (ii) high silicon GJS-500-14, were cast in a geometry containing several plates with different section thicknesses in order to produce microstructural variation. READ MORE

5. 3. Microstructure and deformation behaviour of ductile iron under tensile loading

   Author : Keivan Amiri Kasvayee; Anders E.W. Jarfors; Ehsan Ghassemali; Lennart Elmquist; Kenneth Hamberg; Jönköping University; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ductile iron; digital image correlation DIC ; in-situ tensile test; pit etching; Microscale deformation; micro-crack; finite elements analysis FEA ; cohesive elements;

   Abstract : The current thesis focuses on the deformation behaviour and strain distribution in the microstructure of ductile iron during tensile loading. Utilizing Digital Image Correlation (DIC) and in-situ tensile test under optical microscope, a method was developed to measure high resolution strain in microstructural constitutes. READ MORE

6. 4. The geological conditions for aggregate production, with special focus on blasting and fines production

   Author : Mathias Jern; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; blasting; in situ block size distribution; fines; aggregates; damage; micro crack; fracture; fragmentation;

   Abstract : .... READ MORE

7. 5. Development of Energy-based Damage and Plasticity Models for Asphalt Concrete Mixtures

   Author : Ibrahim Onifade; Björn Birgisson; Linbing Wang; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; energy-based models; damage; X-ray computed tomography; continuum plasticity mechanics CPM; effective micro-crack stress; Transportvetenskap; Transport Science;

   Abstract : Characterizing the full range of damage and plastic behaviour of asphalt mixtures under varying strain-rates and stress states is a complex and challenging task. One reason for this  is partly due to the strain rate and temperature dependent nature of the material as well as the variation in the properties of the constituent materials that make up the composite asphalt mixture. READ MORE