Modelling of Laser Welding Process on Thermoplastic Composites

2015 ◽  
Vol 651-653 ◽  
pp. 1513-1518 ◽  
Author(s):  
Benoit Cosson
Keyword(s):  
Laser Welding ◽  
Carbon Fibers ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Laser Energy ◽  
Welding Process ◽  
Thermoplastic Composites ◽  
Homogeneous Material ◽  
Fiber Volume ◽  
Structural Applications

Thermoplastics composites for structural applications are under growing development from the aerospace (carbon fibers with PEI, PPS or PEEK matrices mainly) to the automotive industry (glass and carbon fibers with PP, PA). The plastic deformation they can provide and the assembly facilities through welding techniques are well appreciated. Among the available welding technics, laser offers the possibility to assemble materials in a precise and localized manner and can be easily automated. However, due to the presence of continuous fibers at a high fiber volume fraction, propagation of the laser energy through the composite that present local variation of fiber volume fraction is not as straight forward as in a homogeneous material. Modelling of the laser welding of a thermoplastic/continuous glass fiber is considered here. The study takes into account the microstructure of the composite in order to evaluate changes in local energy absorption and diffusion directly linked with the thickness. Modelling of the welding process is developed from the representation of the moving laser beam. The beam propagation through the composite thickness is considered thanks to the ray tracing method. The proposed method is able to optimise the welding process in function of the microstructure and the material properties of the welded parts.

Effects of Molding Pressure on the Microstructure and Mechanical Properties of 2D-Cf/SiC Composites by PIP Routes

2008 ◽  
Vol 368-372 ◽  
pp. 1025-1027
Author(s):  
Ke Jian ◽  
Jing Yu Liu ◽  
Zhao Hui Chen ◽  
Qing Song Ma
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Carbon Fibers ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Molding Pressure ◽  
Fiber Volume ◽  
Microstructure And Mechanical Properties ◽  
Carbon Fiber Cloth ◽  
Sic Composites

Carbon fiber cloth reinforced silicon carbide (2D-Cf/SiC) composites were prepared through polycarbosilane(PCS) /divinylbenzene(DVB) pyrolysis with SiC as inactive filler. Effects of the molding pressure on the microstructure and mechanical properties of 2D-Cf/SiC composites were investigated. With increasing molding pressure from 0MPa to 3MPa, the fiber volume fraction of the composites was increased. As a result, the strengths of the composites were enhanced. But when the molding pressure exceeded 3MPa, SiC particles would damage the carbon fibers seriously. Therefore, although the fiber fraction of the composites was increased further, the flexural strengths of the composites were decreased. It was found that the composites fabricated with the molding pressure of 3 MPa exhibited highest flexural strength, reached 319.4 MPa.

Ultrasonic Welding of Glass Fiber Reinforced PP Thermoplastic Composites: An Investigation of the Outer Layer Orientation and the Fiber Volume Fraction

2020 ◽  
Vol 858 ◽  
pp. 3-13
Author(s):  
Murtada Abass A. Alrubaie
Keyword(s):  
Shear Strength ◽  
Glass Fiber ◽  
Outer Layer ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Fiber Volume ◽  
Energy Director ◽  
Welding Pressure

This paper presents an experimental study of the influence of the orientation of the outer layer of polypropeylene (PP) reinforced with E-glass fiber laminate (GF/PP) and the influence of the fiber volume fraction on the quality of the welded joint using an ultrasonic welding process. An orthogonal L 16 array (OA) design of experiment was conducted in this paper based on the Taguchi method to evaluate the effect of the orientation of the outer layer and the fiber volume fraction, on the welding process parameters; the welding energy, the amplitude of vibration, the welding pressure, the holding pressure and the holding time were considered in order to achieve a high weld quality. The experiments were carried out using a 15 kHz ultrasonic welding unit with a maximum supplied power of 4000-Watt. GF/PP laminates with fiber volume fraction of 36% and 46% were used in this paper, and the GF/PP laminates were either unidierctional or had a 90 degree outer layer orienation. A 0.127 mm thick polypropeylene film was used as a flat energy director (ED). The evaluation of the weld quality was measured by the apparent shear strength of the single lap welded joints, and by using laser shearography as a non-destructive inspection technique . The failure mechanism of the single lap joint was monitored, using a high speed digital imaging system. A combination of the highest selected level of welding energy, lowest level of amplitude, lowest level of welding pressure, and the lowest level of both hold time and hold pressure of a unidirectional GF/PP with the lowest fiber volume fraction, were found to achieve a higher apparent shear strength of the welded adherends, as compared with the apparent shear strength obtained with the presence of the flat energy director for the same level of factors. A confirmation experiment was conducted to measure the predicted apparent shear strength and compare it with the measured apparent shear strength from the test.

Microscopic level modeling of induction welding heating mechanisms in thermoplastic composites

2021 ◽  
pp. 089270572110466
Author(s):  
Darun Barazanchy ◽  
Michel van Tooren ◽  
Mohammod Ali
Keyword(s):  
Cross Section ◽  
Carbon Fibers ◽  
Volume Fraction ◽  
Circular Cross Section ◽  
Microscopic Level ◽  
Thermoplastic Composites ◽  
Heating Process ◽  
Fiber Volume ◽  
Electrical Fields ◽  
Solid Loss

Simulation and analysis of electromagnetic induction heating of continuous conductive fiber-based composite materials is used to (in)validate a series of hypotheses on the physics dominating the heating process. The behavior of carbon fibers with and without surrounding polymer in an alternating electromagnetic field is studied at a microscopic level in ANSYS Maxwell using the solid loss to quantify heat generation in the composite material. To limit the number of elements, the fibers are modeled with a polyhedron cross-section instead of a circular cross-section. In addition, each layer is modeled as an layer of fibers, e.g. 20 fibers placed next to each other. The simulations indicate that samples with fibers oriented in 0 and 90 orientation yield a substantial higher solid loss than fibers oriented in the 0 orientation only. The solid loss in both cases is however not enough to explain the level of heating observed in practice. Filling the volumes between fibers with polymer results in greater solid loss than samples with no polymer between the fibers, at equal fiber volume fraction. Note, no contact between fibers is modeled. The conductivity of the polymer is experimentally determined. The lab tests show relatively low finite resistance values in the transverse direction, indicating that the polymer in a composite should not be considered an isolator. The simulations seem to justify the conclusion that heating of thermoplastic composites in an alternating magnetic field rely on currents through the polymer. Without the polymer and subsequently no polymer conductivity, even if the electrical fields are strong there is almost no heat generated. The carbon fibers are required to be in proximity of each other to create the electrical fields that induce the current through the polymer. The heating is determined by the product of current density squared times the resistivity of the polymer.

Experimental investigation of through-thickness resistivity of unidirectional carbon fiber tows

2018 ◽  
Vol 53 (21) ◽  
pp. 2993-3003
Author(s):  
Hong Yu ◽  
Jessica Sun ◽  
Dirk Heider ◽  
Suresh Advani
Keyword(s):  
Electrical Resistivity ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Surface ◽  
Testing System ◽  
Fiber Volume ◽  
Resistivity Model ◽  
Good Agreement

In this study, the influence of type of carbon fiber, sizing amount on the fiber surface and the degree of compaction on the through-thickness electrical resistivity of dry unidirectional carbon fiber tows is investigated to validate the conduction pathways and mechanisms proposed by our previously reported micromechanics electrical resistivity model. An automated experimental setup has been developed and implemented, which measures the electrical resistivity and fiber volume fraction of carbon fiber tows under compression in real time. An extensive experimental study is conducted with five types of commercial PAN-based carbon fibers which vary in fiber diameter, number of fibers in a tow including two unsized fibers and three sized fibers with sizing amount of 0.25% and 1.0% by weight. The fiber volume fraction was increased by compacting the fiber tows using a mechanical testing system (Instron, Norwood, MA). The results show that the fiber sizing and fiber volume fraction impact the through-thickness electrical resistivity of carbon fiber tows. Sized fibers demonstrate 1–2 orders of magnitude higher electrical resistivity than the unsized fibers at lower fiber volume fractions (below 45%), while at higher fiber volume fraction (60%–70%), the electrical resistivity of the two fiber systems tends to be of similar magnitude. Fibers with more sizing (1 wt.%) demonstrated 10 times larger through-thickness resistivity than those with less sizing (0.25 wt.%), indicating the significant impact of fiber sizing on electrical resistivity. The results show good agreement with our micromechanics electrical resistivity model.

Shock Reduction for Electronic Components Within a Projectile

2006 ◽  
Author(s):  
Vinod Chakka ◽  
Mohamed B. Trabia ◽  
Brendan O'Toole ◽  
Srujanbabu Sridharala ◽  
Samaan Ladkany ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Time History ◽  
Electronic Components ◽  
Fiber Volume ◽  
Electronic Package ◽  
Gun Barrel ◽  
Pressure Time ◽  
Supporting Plate

Electronic components within a projectile are subjected to severe loads over extremely short duration. Failure of these components is likely to have negative implications to the projectile or mission. While experimental data can be helpful in understanding the failure phenomena, collecting such data is usually difficult. There are also limitations on the reliability of sensors under these circumstances. Finite element modeling (FEM) can offer a means to better understand the behavior of these components. It can also be used to design better techniques to mitigate the shocks these components are subjected to. A model of a typical projectile and the gun barrel is presented. The projectile is modified to include a payload of a one-pound mass that represents a typical electronic package, which is supported by a plate. The model, which is subjected to a realistic launch pressure-time history, includes the effects of friction between the gun barrel inner surface and the projectile. The effect of the flexibility of the gun barrel on the vibrations of the electronic package is also considered. This paper proposes using a composite plate, with carbon fibers embedded in an epoxy matrix, to reduce the shocks transmitted to the payload. A parametric study of the effects of varying the thickness of the supporting plate and the fiber volume fraction on accelerations and stresses is included.

Manufacture of Fabric Reinforced Thermoplastic Composites with High Fiber Volume Fraction

2013 ◽  
Vol 796 ◽  
pp. 301-305
Author(s):  
An Chang Xu ◽  
Li Min Bao
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Impregnation Method ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
High Fiber ◽  
Molding Method ◽  
Reinforcement Fiber

In fiber reinforced thermosetting plastic (FRP) the fiber volume fraction is always up to 60 percent, but in fiber reinforced thermoplastic (FRTP) it is low to about 30 percent which greatly limit their performance. In this paper, for increasing the fiber volume fraction of thermoplastic composite, a new impregnation method for molding continuous fiber reinforced thermoplastic was explored; the fiber volume fraction was significantly raised to 60 percent which is equal to that of FRPs. Then the tensile property was investigated and made a contrast with FRP with the same reinforcement fiber. The results showed that both the FRP and FRTP composites have the similar tensile properties and indicated that the molding method is effective for FRTP manufacture.

Monitoring of mechanical properties of prestressed glass fiber epoxy composites over 12 months after fabrication

2021 ◽  
pp. 002199832110047
Author(s):  
Mahmoud Mohamed ◽  
Siddhartha Brahma ◽  
Haibin Ning ◽  
Selvum Pillay
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Flexural Strength ◽  
Compressive Residual Stress ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Initial Increase ◽  
Fiber Volume

Fiber prestressing during matrix curing can significantly improve the mechanical properties of fiber-reinforced polymer composites. One primary reason behind this improvement is the generated compressive residual stress within the cured matrix, which impedes cracks initiation and propagation. However, the prestressing force might diminish progressively with time due to the creep of the compressed matrix and the relaxation of the tensioned fiber. As a result, the initial compressive residual stress and the acquired improvement in mechanical properties are prone to decline over time. Therefore, it is necessary to evaluate the mechanical properties of the prestressed composites as time proceeds. This study monitors the change in the tensile and flexural properties of unidirectional prestressed glass fiber reinforced epoxy composites over a period of 12 months after manufacturing. The composites were prepared using three different fiber volume fractions 25%, 30%, and 40%. The results of mechanical testing showed that the prestressed composites acquired an initial increase up to 29% in the tensile properties and up to 32% in the flexural properties compared to the non-prestressed counterparts. Throughout the 12 months of study, the initial increase in both tensile and flexural strength showed a progressive reduction. The loss ratio of the initial increase was observed to be inversely proportional to the fiber volume fraction. For the prestressed composites fabricated with 25%, 30%, and 40% fiber volume fraction, the initial increase in tensile and flexural strength dropped by 29%, 25%, and 17%, respectively and by 34%, 26%, and 21%, respectively at the end of the study. Approximately 50% of the total loss took place over the first month after the manufacture, while after the sixth month, the reduction in mechanical properties became insignificant. Tensile modulus started to show a very slight reduction after the fourth/sixth month, while the flexural modulus reduction was observed from the beginning. Although the prestressed composites displayed time-dependent losses, their long-term mechanical properties still outperformed the non-prestressed counterparts.

scholarly journals Effect of Fiber Volume Fraction on Behavior of Concrete Beams Made with Recycled Concrete Aggregates

2019 ◽  
Vol 253 ◽  
pp. 02004
Author(s):  
Wael Alnahhal ◽  
Omar Aljidda
Keyword(s):  
Fiber Volume Fraction ◽  
Concrete Beams ◽  
Volume Fraction ◽  
Recycled Concrete ◽  
Flexural Behavior ◽  
Beam Specimen ◽  
Rc Beam ◽  
Fiber Volume ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates

This study investigates the effect of using different volume fractions of basalt macro fibers (BMF) on the flexural behavior of concrete beams made with 100% recycled concrete aggregates (RCA) experimentally. A total of 4 reinforced concrete (RC) beam specimens were flexural tested until failure. The parameter investigated included the BMF volume fraction (0%, 0.5%, 1%, and 1.5%). The testing results of the specimens were compared to control beam specimen made with no added fibers. The experimental results showed that adding BMF improves the flexural capacity of the tested beams.

Sign in / Sign up

Export Citation Format

Share Document