An Analysis of Factors Affecting Pull Force for the Pultrusion of Graphite/Epoxy Composites

Abstract

The influence of process parameter settings on the pull force required for the pultrusion of two epoxy resin systems reinforced with unidirectional graphite fiber was investigated. Experiments were conducted using the Shell EPON 9310/9360/537 epoxy resin system and the Shell EPON 9420/9470/537 epoxy resin system. Five independent factors—fiber volume, line speed, die zone I temperature, die zone 2 temperature, and die zone 3 temperature—were examined in each study. Regression analysis was used to iden tify the factors and factor interactions that influence the pull force required for the pultru sion of each resin system and to develop mathematical models to describe the pull force. The models indicated that process variable interactions were especially significant. Re sponse surface methods were used to illustrate the nature of the interactions. Additional statistical techniques were employed to investigate the influence of resin viscosity on the pull force and the influence of pull force on the four-point flexural strength of the com posites produced.

Polymer Composite Manufacturing Using a Pultrusion Process: A Review

“…The pulling force occurs starting from fibre creel until the die inlet and mostly occurs when cross linking reaction between polymer Science Publications AJAS molecules inside heated die . The factors that influenced the pulling speed of the composites during pultrusion process is frictional force, viscous force and internal die pressure (Lackey and Vaughan, 1994). When the velocity of the pulling speed reduces, the damage on the pultruded material can be reduced (Carlone and Palazzo, 2008).…”

Computational Approaches for Modeling the Multiphysics in Pultrusion Process

“…Pull Force Model. As aforementioned, four different contributions to the overall pulling force in pultrusion have been identified in the literature [2,3,[14][15][16][17][18][19][20][21]: the collimation force col , the bulk compaction force bulk , the viscous drag vis , and the frictional force fric . These contributions are strictly related to the geometrical features of the die-work piece system and to the resin transitions from liquid to gel and then solid status, as schematized in Figure 3.…”

“…It should be noted that the value of the friction coefficient depends on the DOC during the resin gelation and further varies at the glass transition. However, due to the lack of thorough experimental data, generally the averaged values are utilized [14][15][16][17][18][19][20][21]. Regarding the magnitude of the contact pressure, is considered to be affected by two contrasting conditions: the transverse thermal expansion of the composite due to the increase in temperature and pressure and the resin chemical shrinkage related to crosslinking reaction.…”

“…Lackey and Vaughan carried on an extensive experimental and statistical investigation on the influence of process parameters on the pulling force and flexural strength of pultruded products, employing a five-factor half-factorial central composite design (CCD). It was concluded that the process parameters affect the pulling force according to complex interactions whose overall effect may vary significantly using resin systems characterized by different cure kinetics [15]. Considering the elevated number of variables involved in the aforementioned problem, a satisfactory experimental analysis could result in undesired time and money spending.…”

“…Several researchers have performed numerical and experimental investigations on different aspects inherent to the pultrusion process, mainly focusing on issues related to heat transfer and cure [5][6][7][8][9][10][11], pressure distribution [12,13], and pulling force [14][15][16][17][18][19][20]. However, proposed models often neglect the interactions between involved phenomena, on the base of some simplifying assumptions.…”