Effects of temperature on a pultruded FRP composite

Abstract

As polymer matrix composites are quickly becoming a viable alternative in civil applications where accurate structural design is quite complex, a good understanding of the behaviour of such materials is necessary. In any civil application, both environmental and design conditions need to be assessed and depending on those conditions, suitable materials for the design can be selected. Composite structures that are exposed to the environment tend to vary quite significantly for their operating temperatures. A significant cause for variation in operating temperature of composite structures is their general exposure to temperatures generated in service. This paper investigates the effects of temperature on the physical and mechanical properties of a pultruded fibre reinforced polymer (FRP) composite that is successfully developed and integrated into various applications in the civil and electrical industries. Experimental results show that the flexural strength of the material decreases linearly to approximately 28% of its initial strength within the experimental range of 20-105°C. Thus tensile strength, compressive strength and bending moment are also expected to decrease linearly at a proportional rate. In collaboration with these results, temperature data were recorded over an approximate 4-day period and a brief analysis of the composite material confirmed that at high operating temperatures, it is not likely that the stresses created at maximum loading will exceed the strength capacity of a composite structure. However, modifications may be required to compensate for losses in modulus at elevated temperatures, depending on the structure requirements and specifications.