Sökning: "Roberts Joffe"

Visar resultat 1 - 5 av 16 avhandlingar innehållade orden Roberts Joffe.

  1. 1. Matrix cracking and interfacial debonding in polymer composites

    Författare :Roberts Joffe; Luleå tekniska universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Polymeric Composite Materials; Polymera konstruktionsmaterial;

    Sammanfattning : .... LÄS MER

  2. 2. Damage accumulation and stiffness degradation in composite laminates

    Författare :Roberts Joffe; Luleå tekniska universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Polymeric Composite Materials; Polymera konstruktionsmaterial;

    Sammanfattning : In the presented thesis analytical modeling of elastic properties degradation and modeling of damage evolution in composite laminates is performed. Transverse cracking initiation on a fiber/matrix level is briefly studied by testing model composites and cross-ply laminates. LÄS MER

  3. 3. Development of Constituents for Multi-functional Composites Reinforced with Cellulosic Fibers

    Författare :Zainab Al-Maqdasi; Roberts Joffe; Nazanin Emami; Liva Pupure; Yvonne Aitomäki; Luleå tekniska universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cellulose fibers; multi-functional; composites; nano-reinforcement; thermoplastics; development; Polymeric Composite Materials; Polymera kompositmaterial;

    Sammanfattning : Bio-basedcomposites are being increasingly used in applications where weight saving,and environmental friendliness is as important as structural performance. Obviously, bio-based materials have their limitations regarding durability and stability of the properties,but their potential in use for advanced applications can be expanded if they were functionalized and considered beyond their structural performance. LÄS MER

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

    Författare :Nawres Al-Ramahi; Roberts Joffe; Janis Varna; Lars Mikkelsen; Luleå tekniska universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 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

  5. 5. Numerical stress analysis in hybrid adhesive joint with non-linear materials

    Författare :Nawres Al-Ramahi; Roberts Joffe; Janis Varna; Rickard Östlund; Luleå tekniska universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Polymeric Composite Materials; Polymera kompositmaterial;

    Sammanfattning : This thesis presents systematic numerical study of stresses in the adhesive of a single-lap joint subjected to various loading scenarios (mechanical and thermal loading). The main objective of this work is to improve understanding of the main material and geometrical parameters determining performance of adhesive joint for the future analysis of failure initiation and development in these structures. LÄS MER