Mechanical properties of discontinuous fiber reinforced thermoplastics. II. Random-in-plane fiber orientation

1975 ◽  
Vol 15 (6) ◽  
pp. 428-436 ◽  
Author(s):  
Bruce F. Blumentritt ◽  
Ban T. Vu ◽  
Stuart L. Cooper
Keyword(s):  
Mechanical Properties ◽  
Fiber Orientation ◽  
Fiber Reinforced ◽  
Discontinuous Fiber ◽  
Reinforced Thermoplastics ◽  
Fiber Reinforced Thermoplastics

scholarly journals A new numerical method for the tensile property analysis of discontinuous fiber-reinforced thermoplastics

2021 ◽  
Vol 30 ◽  
pp. 2633366X2097749
Author(s):  
Dawei Zhang ◽  
Peng Qu ◽  
Yuxi Jia
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Fiber Orientation ◽  
Particle Model ◽  
Fiber Reinforced ◽  
Discontinuous Fiber ◽  
Model Size ◽  
Reinforced Thermoplastics ◽  
Fiber Reinforced Thermoplastics ◽  
Good Agreement

For predicting the mechanical properties of discontinuous carbon fiber-reinforced thermoplastics (DCFRTP), it is essential to consider the microstructure, including the fiber orientation and the properties of the constituting materials. In the present study, a heterogeneous particle model, considering the microscopic factors, is constructed on the basis of the peridynamic (PD) theory to investigate the tensile properties of DCFRTP. Two kinds of randomly oriented DCFRTP, with different constituents and volume fractions of carbon fiber, are used for the verification of this numerical model. A comparison between the PD simulations and the experimental results shows a good agreement. The effect of the model size on the prediction is discussed.

Coupling of Mold Flow Simulations with Two-Scale Structural Mechanical Simulations for Long Fiber Reinforced Thermoplastics

2015 ◽  
Vol 825-826 ◽  
pp. 655-662 ◽  
Author(s):  
Fabian Buck ◽  
Barthel Brylka ◽  
Viktor Müller ◽  
Timo Müller ◽  
Andrew N. Hrymak ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fiber Orientation ◽  
Mechanical Analysis ◽  
Fiber Reinforced ◽  
Micro Computed Tomography ◽  
Simulation Process ◽  
Orientation State ◽  
Orientation Tensors ◽  
Reinforced Thermoplastics ◽  
Fiber Reinforced Thermoplastics

The entire simulation process for long fiber reinforced thermoplastics is examined to determine the effective mechanical properties which are influenced by the microstructural fiber orientation state. Therefore, flow and fiber orientation simulations are conducted and the obtained fiber orientation tensors are used in two-scale structural simulations. The fiber orientation distributions as well as the mechanical properties are compared with micro-computed tomography data and results from threepoint bending tests performed by dynamical mechanical analysis (DMA), respectively. The validated results show that prediction of the essential mechanical properties is possible with the applied combinated methods and that the knowledge of the fiber orientation and its gradients is of crucial importance for the entire simulation process.

scholarly journals Calibration of Fiber Orientation Simulations for LFT—A New Approach

2020 ◽  
Vol 4 (4) ◽  
pp. 163
Author(s):  
Fabian Willems ◽  
Philip Reitinger ◽  
Christian Bonten
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Process Simulation ◽  
Fiber Orientation ◽  
Model Parameters ◽  
Fiber Reinforced ◽  
Orientation Model ◽  
Fiber Microstructure ◽  
Reinforced Thermoplastics ◽  
Fiber Reinforced Thermoplastics

Short fiber reinforced thermoplastics (SFT) are extensively used due to their excellent mechanical properties and low processing costs. Long fiber reinforced thermoplastics (LFT) show an even more interesting property profile and are increasingly used for structural parts. However, their processing by injection molding is not as simple as for SFT, and their anisotropic properties resulting from the fiber microstructure (fiber orientation, length, and concentration) pose a challenge with regard to the engineering design process. To reliably predict the structural mechanical properties of fiber reinforced thermoplastics by means of micromechanical models, it is also necessary to reliable predict the fiber microstructure. Therefore, it is crucial to calibrate the underlying prediction models, such as the fiber orientation model, within the process simulation. In general, these models may be adjusted manually, but this is usually ineffective and time-consuming. To overcome this challenge, a new calibration method was developed to automatically calibrate the fiber orientation model parameters of the injection molding simulation by means of optimization methods. This optimization routine is based on experimentally determined fiber orientation distributions and leads to optimized parameters for the fiber orientation prediction model within a few minutes. To better understand the influence of the model parameters, different versions of the fiber orientation model, as well as process and material influences on the resulting fiber orientation distribution, were investigated. Finally, the developed approach to calibrate the fiber orientation model was compared with a classical approach, a direct optimization of the whole process simulation. Thereby, the new optimization approach shows a calculation time reduced by the factor 15 with comparable error variance.

scholarly journals Influence of the Initial Fiber Orientation on the Weld Strength in Welding of Glass Fiber Reinforced Thermoplastics

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Isabel Fiebig ◽  
Volker Schoeppner
Keyword(s):  
Glass Fiber ◽  
Fiber Orientation ◽  
Weld Strength ◽  
Fiber Reinforced ◽  
Hot Plate ◽  
Glass Fiber Reinforced ◽  
Vibration Welding ◽  
Reinforced Thermoplastics ◽  
Fiber Reinforced Thermoplastics ◽  
Initial Fiber

The welding factors are significantly lower in welding of fiber reinforced thermoplastics than in welding of unreinforced thermoplastics due to the fiber orientation in the weld. This paper presents results from investigations on the influence of the initial fiber orientation on the weld strength in hot plate and vibration welding for glass fiber reinforced polypropylene and polyamide 6. Injection molded specimens are compared to specimens with main initial fiber orientation being longitudinal and transverse to the joining direction. The results of CT analysis of the fiber orientation in the weld show the opportunity to achieve a higher weld strength by using specimens with fibers being initially oriented longitudinally to the joining direction. The influence of the initial fiber orientation in the parts to be welded on the weld strength in hot plate welding is more distinct than in vibration welding.

Effect of Press Condition on the Mechanical Properties of GFRTP Molded by the Melted Thermoplastic-Resin Transfer Molding

2018 ◽  
Vol 774 ◽  
pp. 367-372
Author(s):  
Kazuto Tanaka ◽  
Akihiro Hirata ◽  
Tsutao Katayama
Keyword(s):  
Mechanical Properties ◽  
Shell Structure ◽  
Low Cost ◽  
Resin Transfer Molding ◽  
Outer Shell ◽  
Fiber Reinforced ◽  
Thermoplastic Resin ◽  
Transfer Molding ◽  
Reinforced Thermoplastics ◽  
Fiber Reinforced Thermoplastics

The application of Fiber Reinforced Thermoplastics (FRTP) is expected to reduce the weight of automobiles. The press and injection hybrid molding method was developed to mold FRTP with high strength and high stiffness by giving complicated shapes such as ribs and bosses to the outer shell structure of FRTP with continuous fiber. However, as this method uses high-cost FRTP laminated sheets, it is necessary to develop a low-cost FRTP manufacturing process. In this study, we aim at the development of Melted Thermoplastic-Resin Transfer Molding (MT-RTM) to mold FRTP with complicated shape at low cost by injecting melted short fiber reinforced thermoplastics into dry fabric. The effects of press condition on the mechanical properties of GFRTP molded by MT-RTM were clarified by bending tests. GFRTP molded at high mold temperature and high closing speed showed high mechanical properties because of good impregnation of injection resin into continuous fabric in the outer shell structure.

scholarly journals Uncertainty quantification of fiber orientation distribution measurements for long-fiber-reinforced thermoplastic composites

2017 ◽  
Vol 52 (13) ◽  
pp. 1781-1797 ◽  
Author(s):  
Bhisham N Sharma ◽  
Diwakar Naragani ◽  
Ba Nghiep Nguyen ◽  
Charles L Tucker ◽  
Michael D Sangid
Keyword(s):  
Cross Sections ◽  
Fiber Orientation ◽  
Surface Preparation ◽  
Orientation Distribution ◽  
Elastic Stiffness ◽  
Thermoplastic Composites ◽  
Fiber Reinforced ◽  
Fiber Orientation Distribution ◽  
Discontinuous Fiber ◽  
Reinforced Thermoplastics

We present a detailed methodology for experimental measurement of fiber orientation distribution in injection-molded discontinuous fiber composites using the method of ellipses on two-dimensional cross sections. Best practices to avoid biases occurring during surface preparation and optical imaging of carbon-fiber-reinforced thermoplastics are discussed. A marker-based watershed transform routine for efficient image segmentation and the separation of touching fiber ellipses is developed. The sensitivity of the averaged orientation tensor to the image sample size is studied for the case of long-fiber thermoplastics. A Mori–Tanaka implementation of the Eshelby model is then employed to quantify the sensitivity of elastic stiffness predictions to biases in the fiber orientation distribution measurements.

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