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Visar resultat 1 - 5 av 6 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Comprehensive numerical analysis of stress state in adhesive layer of joint including thermal residual stress and material non-linearity

    Författare :Nawres Jabar Al-Ramahi; Roberts Joffe; Janis Varna; Lars Mikkelsen; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Single-lap adhesive joint; Double-lap adhesive joint; Unbalanced bi-material DCB; Residual thermal stresses; Finite element method; Crack path; Crack closure; Polymeric Composite Materials; Polymera kompositmaterial;

    Sammanfattning : The main objective of this work is to improve understanding of the stress state in the adhesive layer of bonded joints and identify key parameters which govern performance of adhesive joints. This information is crucial for the prediction of the failure initiation and propagation with the further estimation of the durability and strength of adhesively bonded structures. LÄS MER

  3. 2. On the Role of Interfaces in Small Scale Plasticity

    Författare :Carl F. O. Dahlberg; Jonas Faleskog; Lars Pilgaard-Mikkelsen; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : The strong evidence for a size dependence of plastic deformation in polycrystalline metalsis the basis for the research presented in this thesis. The most important parameter for this, and arguably also the most well known, is the grain size. As the size of the grains in a microstructure is decreased the yield stress increases. LÄS MER

  4. 3. Testing and analysis of composites with 3D woven reinforcement

    Författare :Tomas Ekermann; Malin Åkermo; Stefan Hallström; Lars Pilgaard Mikkelsen; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 3D weave; finite element; manufacturing; yarn path; weaving; failure criteria; mechanical testing; 3D väv; finita element; tillverkning; trådbanor; vävning; brottkriterier; mekanisk provning; Farkostteknik; Vehicle and Maritime Engineering;

    Sammanfattning : Composites with three-dimensional (3D) reinforcement have several benefits, compared to laminated composites. Their through-thickness reinforcement increase the out-of-plane properties significantly and could eliminate problems with delaminations. Also, these composites have proven to have great damage tolerance and energy absorption. LÄS MER

  5. 4. Characterisation of thermally induced degradation of high-temperature polymers and composites

    Författare :Valeri Ivanov Petkov; Patrik Fernberg; Lars Pilgaard Mikkelsen; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Polymeric Composite Materials; Polymera kompositmaterial;

    Sammanfattning : This project aimed to broaden the knowledge of high-temperature polymers and composites when exposed to elevated temperatures and an oxygen-containing atmosphere. The main accent has been on thermosetting polyimide resins reinforced with carbon fibers. LÄS MER

  7. 5. Improving the efficiency of eigenvector-related computations

    Författare :Angelika Beatrix Schwarz; Lars Karlsson; Bo Kågström; Carl Christian Kjelgaard Mikkelsen; Miroslav Tůma; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; high-performance computing; standard non-symmetric eigenvalue problem; triangular Sylvester equation; tiled algorithms; task parallelism;

    Sammanfattning : An effective strategy in dense linear algebra is the design of algorithms as tiled algorithms. Tiled algorithms that express the bulk of the computation as matrix-matrix operations (level-3 BLAS) have proven successful in achieving high performance on cache-based architectures. LÄS MER