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Academic Ceremony 2021

8th of October was the Academic Ceremony at BTH with promotion of PhD’s and installation of professors among other things on the agenda. From Product Development Research Lab and the research subject of Mechanical Engineering we were very happy to see the installation of two new professors in Marco Bertoni, and Sophie Hallstedt. We also […]

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Studenter prisade av Sparbanksstiftelsen Kronan

På den årliga stipendieutdelningen från Sparbanksstiftelsen Kronan (i år online pga pandemin) fick fyra examensarbeten från BTH Maskinteknik priser. 100.000 kr Johan Olsson och Axel Sjöberg (civilingenjör) för arbetet “In-house glove recycling: Eliminating a waste stream with a circular approach“. Handledare vid BTH Maskinteknik var Christian Johansson. Johan Olsson och Axel Sjöberg (civilingenjör) för arbetet […]

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Peeling of metal foil from a compliant substrate

Abstract Large displacement peel was studied for cases where a compliant substrate leads to a large value of the root rotation. An existing simplified beam model to calculate the peel fracture energy was modified to allow for a kinematic hardening beam model of the foil. The steady-state peel force and the root rotation were used […]

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Trouser tear testing of thin anisotropic polymer films and laminates

Abstract This research has investigated the essential work of fracture (EWF) from trouser tear test of polyethylene terephthalate (PET), low-density polyethylene (LDPE) films and their corresponding laminate using a convenient cyclic tear test method. Propagation of tear crack in these thermoplastics deflects from the initial crack path due to the material anisotropy. An improvement to […]

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Congratulations Eskil Andreasson, Doctor of Philosophy!

Eskil Andreasson successfully defended his PhD thesis “Mechanics and Failure in Thin Material Layers –  Towards Realistic Package Opening Simulation” in front of a full house and grading committee, and after thorough questioning by the opponent Gabriella Bolzon (Politecnic University of Milan, Italy) Abstract The final goal of this PhD-work is an efficient and user-friendly […]

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Experimental and numerical assessment of the work of fracture in injection-moulded low-density polyethylene

ABSTRACT The fracture mechanics properties of injection-moulded low-density polyethylene (LDPE) sheets were investigated both experimentally and numerically. The total work of fracture was determined experimentally, by means of fracture mechanics testing of sheets of injection-moulded LDPE with side cracks of different lengths. A multi-specimen method, proposed by Kim and Joe (1987), was employed. The total […]

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Anisotropic Elastic-Viscoplastic Properties at Finite Strains of Injection-Moulded Low-Density Polyethylene

ABSTRACT Injection-moulding is one of the most common manufacturing processes used for polymers. In many applications, the mechanical properties of the product is of great importance. Injection-moulding of thin-walled polymer products tends to leave the polymer structure in a state where the mechanical properties are anisotropic, due to alignment of polymer chains along the melt […]

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Simulation of thin aluminium-foil in the packaging industry

ABSTRACT This work present an approach of how to account for the anisotropic mechanical material behaviour in the simulation models of the thin aluminium foil layer (≈10 μm) used in the Packaging Industry. Furthermore, the experimental results from uniaxial tensile tests are parameterised into an analytical expression and the slope of the hardening subsequently extended […]

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Ab initio and classical atomistic modelling of structure and defects in crystalline orthorhombic polyethylene: Twin boundaries, slip interfaces, and nature of barriers

ABSTRACT We study the stability of twin boundaries and slip in crystalline orthorhombic polyethylene by means of density functional theory (DFT), using a nonempirical, truly nonlocal density function, and by means of classical molecular dynamics (MD). The results show that, in accordance with experimental observations, there is a clear preference to chain slip over transverse […]

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Modeling and Study of Fracture and Delamination in a Packaging Laminate

ABSTRACT In this work, a packaging laminate consisting of LDPE (Low Density Polyethylene), Al-foil (Aluminum foil) is focused, and failure due to necking in substrates and interfacial delamination under loading are considered. A coupled elasto-plasticity damage and fracture constitutive model is combined. The proposed constitutive model is incorporated into the FEM code ABAQUS and utilized […]

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