0000000000276445

AUTHOR

Laura Stiebra

showing 2 related works from this author

Anisotropy of the stiffness and strength of rigid low-density closed-cell polyisocyanurate foams

2016

The cells of polymer foams are usually extended in the foam rise direction, causing a geometrical anisotropy, the degree of which, characterized by the cell aspect ratio R, depends on foam density and production method. Such elongated cell shape translates into anisotropy of the mechanical properties of foams. Rigid low-density closed-cell polyisocyanurate foams of apparent density ranging from ca. 30 to 75 kg/m3, containing polyols derived from renewable resources, have been produced and tested for the stiffness and strength in the foam rise and transverse directions in order to experimentally characterize their mechanical anisotropy. Analytical relations for foams with rectangular paralle…

Materials sciencebusiness.product_categoryPolyisocyanurateTapering02 engineering and technology0203 mechanical engineeringlcsh:TA401-492medicineGeneral Materials ScienceComposite materialAnisotropyPhysics::Computational Physicschemistry.chemical_classificationMechanical EngineeringStiffnessPolymer021001 nanoscience & nanotechnologyAspect ratio (image)Condensed Matter::Soft Condensed MatterParallelepipedTransverse plane020303 mechanical engineering & transportschemistryMechanics of Materialslcsh:Materials of engineering and construction. Mechanics of materialsmedicine.symptom0210 nano-technologybusinessMaterials & Design
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The effect of a circular hole on the tensile strength of neat and filled rigid PUR foams

2015

Abstract In order to elucidate the effect of stress concentration on the tensile strength of rigid polyurethane (PUR) foams, specimens with open circular holes and different ratios of hole diameter to specimen width were tested in tension. The reduction in the net-section strength of the specimens with a center hole ranged from 1% to 18% for neat foams and from 18% to 28% for foams produced from a nanoclay-filled PUR. The finite fracture mechanics approach, based on simultaneous application of the strength and fracture mechanics criteria of failure, yielded a reasonably accurate prediction of foam strength in the presence of stress concentration.

Materials scienceTension (physics)Applied MathematicsMechanical EngineeringFracture mechanicsCondensed Matter PhysicsFinite fracture mechanicschemistry.chemical_compoundCircular holechemistryUltimate tensile strengthGeneral Materials ScienceComposite materialOpen holePolyurethaneStress concentrationTheoretical and Applied Fracture Mechanics
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