The effect of strain rate on the compressive behaviour of epoxy compound epy®
Magdalena Urbaniak, Karol Grudziński Politechnika Szczecińska, Wydział Mechaniczny, Katedra Mechaniki i Podstaw Konstrukcji Maszyn al. Piastów 19, 70-310 Szczecin
Quarterly No. 4, 2006 pages 24-28
DOI:
keywords: epoxy compound, cure conditions, compressive strain rate, mechanical properties
abstract The object of the investigations described in this paper is a special epoxy material of the trade name EPY® that has been applied to foundation chocks of ship’s machinery and installations, and also to many other heavy land-based machines lately. Casting of foundation chocks from this material on the spot, directly under an installed and suitably positioned object (e.g. ship’s main engine) considerably simplifies the assembling technology of heavy machines. This technology offers a number of technical, economic and operational advantages. The mechanical properties of this material are determined to a large extent by factors bound with the production technology of foundation chocks and especially by curing conditions as well as by operating conditions, mainly by the temperature and strain rate. The course of curing process for EPY® material was investigated by DSC method. The obtained DSC thermograms are shown in Figure 1. The mechanical characteristics of the material for its different cure states at various strain rates were determined by a computerized testing machine INSTRON. The results of these tests are shown in Figures 2, 3 and 6. Strain rate effect on the mechanical characteristics of the material was subjected to an analyse. The values of some chosen compressive strength parameters, which are essential for practical applications of EPY® material both cured at 22 ±1°C (Fig. 4) and postcured at various temperatures (from 40 to 100°C) (Fig. 6), were determined. An analysis of the results obtained from the tests showed that the mechanical properties of EPY® material can be well described by means of the Eyring equation (1) (Figs. 5 and 7). This means that compressive strength of the investigated material in a given curing state linearly increases with the logarithm of strain rate (Fig. 5). An increase of the postcuring temperature of the material (in the temperatures ranging from 40 to 100°C) results in diminishing its sensitivity to the change of strain rate (Fig. 7). The presented paper makes it possible to better understand the essential mechanical properties of EPY® material treated as a structural material and used to assemble heavy machines and installations which operate in various thermal and loading conditions.