Rigidity and Damage Evolution of Long Fibre Reinforced Polypropylene Made by Direct Processing Route (LFT-D)

2017 ◽  
Vol 742 ◽  
pp. 3-8
Author(s):  
Kay André Weidenmann ◽  
Stefan Dietrich ◽  
Manfred Grigo ◽  
Peter Elsner

In order to reduce fuel consumption due to environmental aspects, weight of automotive components has to be reduced. Fibre reinforced polymers have high potential to contribute to this aim as they feature a high ratio of stiffness to weight. The direct processing route for long fibre reinforced polymers is a potential process for the net shape series production of automotive parts. To retain safety and comfort, the material properties of polymers processed in such a way have to be investi-gated thoroughly implementing a deeper understanding of elastic response and damage mechanisms. This work deals with glass fibre reinforced polypropylene manufactured by a direct LFT processing route (D-LFT). After introducing basic properties, studies to determine damage evolution are presented. In this regard, the decrease of stiffness with increasing strain was analyzed using tensile tests featuring loading-unloading cycles. The materials properties have been correlated to fibre orientation measurements from X-ray computed tomography. The stiffness decrease is compared to stiffness measurements carried out by ultrasonic phase spectroscopy (UPS) tests, carried out on juvenile, undamaged specimens. This method is used in this study for the first time to describe the elastic properties of long fibre reinforced thermoplastics.

2019 ◽  
Vol 827 ◽  
pp. 493-498
Author(s):  
Kazuto Tanaka ◽  
Toshihide Kiyama ◽  
Tsutao Katayama

The application of Glass Fibre Reinforced Thermoplastics (GFRTP) is expected to reduce the weight of automobiles. In order to use GFRTP for automotive parts, it is essential to apply Computer Aided Engineering (CAE) technology. Until now, prepreg sheets with thermosetting resin matrix are assumed to be used for materials in simulation software. When FRTP is applied for materials in simulation software, it is required to grasp the characteristics of FRTP under moulding temperature. In our previous study, a system capable of evaluating the tensile properties of FRTP laminates at moulding temperatures had been developed and their tensile properties had been evaluated. Bending stiffness under moulding temperature is also required for simulation software. While bending stiffness can be determined using Young's modulus for isotropic materials, thermoplastic prepregs have large anisotropy, especially at moulding temperature. In this study, a system that enables self-weight deflection test of thermoplastic resin laminate under moulding temperature was developed and self-weight deflection characteristics of plain weave GFRTP were evaluated. The analysed results in which the bending stiffness under the moulding temperature of GFRTP was taken into account, gave the most suitable results to the experimental results.


Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1136
Author(s):  
Marcel Carpio ◽  
Jessica Calvo ◽  
Omar García ◽  
Juan Pablo Pedraza ◽  
José María Cabrera

Designing a new family of advanced high-strength steels (AHSSs) to develop automotive parts that cover early industry needs is the aim of many investigations. One of the candidates in the 3rd family of AHSS are the quenching and partitioning (QP) steels. These steels display an excellent relationship between strength and formability, making them able to fulfill the requirements of safety, while reducing automobile weight to enhance the performance during service. The main attribute of QP steels is the TRIP effect that retained austenite possesses, which allows a significant energy absorption during deformation. The present study is focused on evaluating some process parameters, especially the partitioning temperature, in the microstructures and mechanical properties attained during a QP process. An experimental steel (0.2C-3.5Mn-1.5Si (wt%)) was selected and heated according to the theoretical optimum quenching temperature. For this purpose, heat treatments in a quenching dilatometry and further microstructural and mechanical characterization were carried out by SEM, XRD, EBSD, and hardness and tensile tests, respectively. The samples showed a significant increment in the retained austenite at an increasing partitioning temperature, but with strong penalization on the final ductility due to the large amount of fresh martensite obtained as well.


2021 ◽  
Vol 36 (2) ◽  
pp. 213-218
Author(s):  
M. D. D. Boudiaf ◽  
L. Hemmouche ◽  
M. A. Louar ◽  
A. May ◽  
N. Mesrati

Abstract In this study, the strain rate sensitivity of a discontinuous short fiber reinforced composite and the strain rate effect on the damage evolution are investigated. The studied material is a polymeric composite with a polyamide 6.6 matrix reinforced with oriented randomly short glass fibers at a 50% weigh ratio (PA6.6GF50). Tensile tests at low and high strain rate are conducted. In addition, interrupted tensile tests are carried out to quantify the damage at specific stress levels and strain rates. To perform the interrupted tensile tests, an intermediate fixture is realized via double notched mechanical fuses with different widths designed to break at suitable stress levels. The damage is estimated by the fraction of debonded fibers and matrix fractures. Based on the experimental observations, it is concluded that the ultimate stress and strain, and the damage threshold are mainly governed by the strain rate. Furthermore, it is established that the considered composite has a non-linear dynamic behavior with a viscous damage nature.


2019 ◽  
Vol 33 (12) ◽  
pp. 1603-1628
Author(s):  
Sarah Mosey ◽  
Feras Korkees ◽  
Andrew Rees ◽  
Gethin Llewelyn

Due to the increasing demands on automotive components, manufacturers are relying on injection moulding components from fibre-reinforced polymers in an attempt to increase strength to weight ratio. The use of reinforcing fibres in injection moulded components has led to component failures whereby the material strength is hampered through the formation of weldlines which are also a problem for unreinforced plastics. In this study, an industrial demonstrator component has the injection locations verified through a combination of fibre orientation tensor simulation and optical microscopy analysis of key locations on the component. Furthermore, the automotive component manufactured from 30% glass fibre–reinforced polyamide 6-6 is simulated and optimized through a Taguchi parametric study. A comparison is made between the component, as it is currently manufactured, and the optimum processing parameters determined by the study. It was found that the component can be manufactured with roughly 7.5% fewer weldlines and with a mould fill time 132 ms quicker than the current manufacturing process.


Author(s):  
Christian Gusenbauer ◽  
Michael Reiter ◽  
Bernhard Plank ◽  
Dietmar Salaberger ◽  
Sascha Senck ◽  
...  

Author(s):  
Naoya Tada ◽  
Takeshi Uemori

Gray cast iron has been used as a component in various mechanical parts, such as the blocks and heads of automobile and marine engines, cylinder liners for internal combustion engines, and machine tool bases. It is desirable because of its good castability and machinability, damping characteristics, and high ratio of performance to cost. On the other hand, the weak graphite flakes present in gray cast iron act as stress concentrators and negatively affect the strength of this material. It is therefore important to know the relationship between the distribution of graphite flakes and the strength or fracture of gray cast iron. In this study, a tensile test of gray cast iron was carried out using a plate specimen in a scanning electron microscope, and the microscopic deformation was observed on the surface of specimen. Particularly, the change in the size of graphite flakes during the tensile test was examined, and the observed trend was discussed. We found from the experimental results that the dimensional changes in the graphite flakes varied in the observed area, and that the final fracture occurred in an area where a relatively large dimensional change was observed. This suggests that the fracture location or the critical parts of gray cast iron, can be predictable from the dimensional changes of the graphite flakes at an early stage of deformation.


2017 ◽  
Vol 8 (1) ◽  
pp. 28-37 ◽  
Author(s):  
Radhikesh Prasad Nanda ◽  
Hasim Ali Khan ◽  
Apurba Pal

The out-of-plane performances of brick masonry panels with different retrofitting patterns using glass fibre reinforced polymers (GFRP) have been studied under three-point loading test. The panels were retrofitted on one side and both sides with different geometric configurations. The retrofitted specimens increased the failure load from 19.6 kN (UR) to 79.2 kN. It was observed that the flexural strength of the retrofitted patterns increased from 31.58% to 150% when compared to un-retrofitted specimens. Also, the bending moment of the retrofitted panels increased from 5.94 kNm to 8.96 kNm when retrofitted with one side, while it goes up to 14.88 kNm when retrofitted with both side as compared to un-retrofitted specimens. Further, it also observed that the panel with cross retrofitting showed more efficiency in terms of flexural strength, bending moment, stiffness and deformation capacity.


Sign in / Sign up

Export Citation Format

Share Document