Abstract:In this paper, a three-dimensional thermo-viscoelastic constitutive equation is used to simulate and analyze the hot stamping process of thermoplastic resin matrix composites. Dynamic mechanical analyzer (DMA) was used to measure the relaxation behavior of resin matrix at different temperatures. Then, the relaxation times and the weight factors of the resin matrix were obtained by regression analysis of the data of the resin matrix relaxation behavior using genetic intelligent algorithm. According to the class… Show more
“…As in the study of Mao et al, in this study, the probability of damage to the upper and lumbar regions of the specimen increased as the depth increased. 6 Figure 9.Effect of drawing depth on part thickness distribution (T: 159 ° C - V: 90 mm/min - P: 0.4 MPa).…”
Section: Resultsmentioning
confidence: 99%
“…As in the study of Mao et al, in this study, the probability of damage to the upper and lumbar regions of the specimen increased as the depth increased. 6 The effect of different specimen temperatures on the thickness change of deep drawn specimens at 90 mm/min punch speed, 0.4 MPa holding pressure and 25 mm depth is shown in Figure 10. It was determined that the most important parameter affecting the change in part thickness was the specimen temperature.…”
Section: Thickness Distributions At 0 °And 45 °Sections Of the Part A...mentioning
confidence: 99%
“…4 Researchers and manufacturers are investigating the causes of these defects that affect part quality, whether they are within acceptable limits and conducting research to minimize them. 5 Mao et al 6 investigated the forming of glass fiber reinforced PP (Polypropylene) composite laminate at different speeds and temperatures by both experimental and finite element analysis. They determined that as the preheating temperature increased, the stress that the specimen can withstand decreased due to the increase in the matrix relaxation behavior, and the damage rate of the specimen increased after 25 mm depth.…”
When lightweighting studies are examined, thermoplastic matrix composites come to the fore as they have a high specific strength, are recyclable, and can be formed by thermoforming. Some obscurity needs to be overcome for the rapid forming of three-dimensional parts from laminated thermoplastic composites. In this study, deep drawing experiments were carried out to investigate the forming capabilities of continuous glass fiber reinforced polypropylene composite laminates. The parameters of drawing depth, laminate temperature, holding pressure, and punch speed were examined at each three different levels. The effects of these parameters were evaluated on the earing defect and the thickness distribution. It was concluded that the laminate temperature affected both deformations the most. It was determined that all parameters caused a change in flange diameter, but the amount of earing increased with the increase of drawing depth. It was established that inhomogeneous thickness distributions occurred in the part and the highest thickening took place in the curve region.
“…As in the study of Mao et al, in this study, the probability of damage to the upper and lumbar regions of the specimen increased as the depth increased. 6 Figure 9.Effect of drawing depth on part thickness distribution (T: 159 ° C - V: 90 mm/min - P: 0.4 MPa).…”
Section: Resultsmentioning
confidence: 99%
“…As in the study of Mao et al, in this study, the probability of damage to the upper and lumbar regions of the specimen increased as the depth increased. 6 The effect of different specimen temperatures on the thickness change of deep drawn specimens at 90 mm/min punch speed, 0.4 MPa holding pressure and 25 mm depth is shown in Figure 10. It was determined that the most important parameter affecting the change in part thickness was the specimen temperature.…”
Section: Thickness Distributions At 0 °And 45 °Sections Of the Part A...mentioning
confidence: 99%
“…4 Researchers and manufacturers are investigating the causes of these defects that affect part quality, whether they are within acceptable limits and conducting research to minimize them. 5 Mao et al 6 investigated the forming of glass fiber reinforced PP (Polypropylene) composite laminate at different speeds and temperatures by both experimental and finite element analysis. They determined that as the preheating temperature increased, the stress that the specimen can withstand decreased due to the increase in the matrix relaxation behavior, and the damage rate of the specimen increased after 25 mm depth.…”
When lightweighting studies are examined, thermoplastic matrix composites come to the fore as they have a high specific strength, are recyclable, and can be formed by thermoforming. Some obscurity needs to be overcome for the rapid forming of three-dimensional parts from laminated thermoplastic composites. In this study, deep drawing experiments were carried out to investigate the forming capabilities of continuous glass fiber reinforced polypropylene composite laminates. The parameters of drawing depth, laminate temperature, holding pressure, and punch speed were examined at each three different levels. The effects of these parameters were evaluated on the earing defect and the thickness distribution. It was concluded that the laminate temperature affected both deformations the most. It was determined that all parameters caused a change in flange diameter, but the amount of earing increased with the increase of drawing depth. It was established that inhomogeneous thickness distributions occurred in the part and the highest thickening took place in the curve region.
“…One of the widely used models to describe the viscoelastic behavior of materials is the Prony series. The model has been used to describe the viscoelastic behavior of materials under complex conditions like different temperatures, the hygrothermal environment and the curing process [14][15][16][17]. However, in order to accurately describe viscoelastic behavior, a large number of parameters are introduced into Prony series.…”
In the pre-forming process of uncured prepreg laminates with hot press, the compaction stress is an important parameter that affects the performance and quality of the final product. Therefore, it is necessary to explore the compaction response of the prepreg during manufacturing processes. In this study, the compression and relaxation viscoelastic behaviors of uncured prepreg laminates were investigated in different temperatures, displacements, velocities, and thicknesses. The results show that the power law model and the fractional viscoelastic model could accurately describe the compression and relaxation behaviors, respectively. The theoretical fitting curves match very well with experimental data at each condition and the R-squared value is greater than 0.95. The effect mechanism of compression and relaxation viscoelastic behaviors is analyzed and the obtained results could provide a reference for the process of hot press-forming and numerical simulation.
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