The Relationship Between Mechanical Properties and the Method Technique of GFRP Plate by Hand Lay-up Method: Effect of the Workers Experience

The aim of this research was focused on the relationship between the skill of an operator in the hand lay-up molding method and the mechanical properties of the molding composites. Glass fiber reinforced plastic (GFRP) plates were prepared using the hand lay-up method by five inexperience operators. The materials of GFRP included unsaturated polyester resin and chopped glass fiber mat. The working procedure of all operators was recorded by a video camera. Mechanical properties of the GFRP plates were carried out by tensile testing. The load-displacement curve was illustrated, which was used for characterizing the molding technique of various operators. The relationship of working times and mechanical strength of the GFRP was characterized, which impacted on the mechanical properties of the specimens. From the results, the relationship was considered separately in the first half and the second half of the working times. From the results, the step of degassing squeeze out air was significantly influenced the mechanical strength of the GFRP products. Therefore, the degassing step with the iron bar was the most affected on the mechanical properties of the GFRP plate making by the inexperience operator. It can be noted that the fully degassing out of the molding product strongly suggested for the hand lay-up method in order to maintain the high strength of the GFRP products.