Abstract:Advanced fabric reinforced polymer composites find extensive applications in aerospace and structural fields due to their high mechanical properties. A novel stamp forming technique finds extensive use in the hemispherical forming of thermoplastic composites. This study investigates the influence of stamp forming parameters on the formability of thermoplastic composite using Taguchi's robust design and grey relational analysis. Taguchi's orthogonal array was used for designing the forming experiments. Response… Show more
“…When the punch speed was 90 mm/min, the final diameter value of the flange part increased as the circumferential yield strength decreased with the increase of the holding pressure, but the earing amount did not change. Suresh and Kumar 11 reported similar findings in their study. They explained that the increase in holding pressure increased the radial tensile stress and thus caused an increase in flange diameter.Figure 6.Effect of holder pressure on earing defect (H: 25 mm - T: 159 ° C - V: 90 mm/min).Figure 7.Effect of punch speed on earing defect (P: 0.4 MPa - H: 25 mm - T: 159 ° C).…”
Section: Resultssupporting
confidence: 80%
“…However, they also determined that the top and bottom layers of the nonwoven material shifted relatively. Suresh and Kumar 11 investigated the forming of woven glass fiber reinforced PP composite laminates using different mold and specimen temperatures at different holding forces. They studied the drawing ratio and the logarithmic thickness variation.…”
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.
“…When the punch speed was 90 mm/min, the final diameter value of the flange part increased as the circumferential yield strength decreased with the increase of the holding pressure, but the earing amount did not change. Suresh and Kumar 11 reported similar findings in their study. They explained that the increase in holding pressure increased the radial tensile stress and thus caused an increase in flange diameter.Figure 6.Effect of holder pressure on earing defect (H: 25 mm - T: 159 ° C - V: 90 mm/min).Figure 7.Effect of punch speed on earing defect (P: 0.4 MPa - H: 25 mm - T: 159 ° C).…”
Section: Resultssupporting
confidence: 80%
“…However, they also determined that the top and bottom layers of the nonwoven material shifted relatively. Suresh and Kumar 11 investigated the forming of woven glass fiber reinforced PP composite laminates using different mold and specimen temperatures at different holding forces. They studied the drawing ratio and the logarithmic thickness variation.…”
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.
“…Interestingly, the other specimen (panel B), thermoformed at 190 °C with 30 bar of pressure, showed only very few minor microvoids, and the fiber wrinkling was greatly minimized. It should be noted that this fiber wrinkling is a general issue that was already observed when reshaping thermoplastic composites and can be affected by fabric weave patterns, as well as by lay-up sequence. − It is usually caused by the resistance of the reinforcement to take a given shape due to poor fabric drapability. , Figure S24 shows the delamination and cracks of an epoxy-based thermoset composite that undergoes a similar treatment.…”
To develop siloxane-containing vitrimers with fast dynamic characteristics, different mechanistic pathways have been investigated using a range of catalysts. In particular, one siloxane exchange pathway has been found to show a fast dynamic behavior in a useful temperature range (180−220 °C) for its application in vitrimers. The mechanism is found to involve 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) as an organic catalyst in the presence of hydroxyl groups. Using this new mechanistic approach, vitrimers with ultrafast stress-relaxation characteristics (relaxation times below 10 s) have been prepared with a readily available epoxy resin and siloxane-amine hardener. Subsequently, the low viscosity siloxane-containing vitrimer resin enabled the preparation of glass fiber-reinforced vitrimer composites using an industrially relevant vacuum-assisted resin infusion technique. The resulting composite was successfully thermoformed into a new shape, which makes it possible to envision a second life for such highly engineered materials.
“…Researchers have recently studied other approaches for TMC forming. Die-less forming, 3 thermostamping, 4 and stamp forming 5,6 are a few examples.…”
The experimental study of single point incremental forming (SPIF) of a thermoplastic matrix composite (TMC) was presented in this research. The TMC’s matrix was built of polyamide (PA) 6.6, and the reinforcement was 30 wt percent short glass fiber (GF). The TMC was manufactured by hot pressing PA/30 wt percent GF granules to a thickness of 1.5 mm. The impact of SPIF process variables such as forming temperature (60°C–120°C), spindle speed (500 rpm–3000 rpm), wall angle (30°–60°), and step size (0.5 mm–1.5 mm) on forming depth and shrinkage owing to cooling were investigated. The findings revealed that the wall angle is the most effective parameter on TMC forming depth and shrinkage. Furthermore, TMC showed a significant percentage of shrinkage when it is cooled (up to 83.6% of shrinkage).
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