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THE EFFECT OF LOADING RATE AND DIRECTION OF FORMATION ON FRACTURE TOUGHNESS OF RIGID POLYURETHANE FOAMS


LINUL EMANOIL 1, MARSAVINA LIVIU 1
1. "Politehnica" University of Timisoara, Department of Strength of Materials, Blvd. M. Viteazu, No. 1, 300222, Timisoara, Romania

Issue:

JESR, Number 1, Volume XVIII

Section:

Issue No. 1 - Volume 18 (2012)

Abstract:

This paper presents the effect of loading rate, (ELR), and direction of formation, (DF), of rigid polyurethane foams, (PUR 40 and PUR 140), on fracture toughness. Nominal densities of used foams in the experimental program were 140 kg/m3, (for ELS) and 40 kg/m3, (for DF), which is closed-cell rigid foams widely used for sandwich cores. Determination of fracture toughness for Mode I fracture of studied materials has made by three-point bending tests, (3PB), on specimens with notches, at room temperature (20 ± 2 ÂșC). All the specimens were cut from one and the same plate. The specimens were subjected to 3PB at a loading speed of 2 mm/min, except samples for determining the ELR where 2, 20, 200 and 400 mm/min loading speeds were used, and were taken into account the fact that the load must act exactly on the notch direction. All the specimens present brittle failure without plastic deformation.

Keywords:

polyurethane foam, closed cells, fracture toughness, three point bend tests.

Code [ID]:

JESR201201V18S01A0016 [0003602]

Full paper:

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