scholarly journals Pultrusion of Micro-Braided GF/PA6 Yarn

1999 ◽  
Vol 8 (6) ◽  
pp. 096369359900800
Author(s):  
G. Bechtold ◽  
M. Sakaguchi ◽  
K. Friedrich ◽  
H. Hamada
Keyword(s):  
Bending Strength ◽  
Polyamide 6 ◽  
Processing Parameters ◽  
Experimental Investigations ◽  
Mechanical Characterisation ◽  
Reinforced Composite ◽  
Preheating Temperature ◽  
New Type ◽  
Commingled Yarns ◽  
Fibre Matrix

The present paper reports about experimental investigations on a new type of thermoplastic intermediate material (TP-prepreg). Today, most processes for producing fibre reinforced composite parts with thermoplastic matrices require expensive prepregs like pre-impregnated tapes or hybrid yarns (commingled yarns or powder impregnated yarns). The microbraiding technique offers some advantages compared to existing prepregs: Microbraided yarns can be produced directly by the user by a microbraiding process requiring only glass rovings and polymer rovings, and at the same time, the user is free of any restrictions on fibre/matrix combinations or reinforcement fibre content. Glass Fibre/Polyamide 6 (Nylon 6) microbraided yarn was compared to commercially available GF/PA6 tape concerning the use in a pultrusion process. For mechanical characterisation, shear strength and bending strength were determined. The processing parameters such as preheating temperature, heated die temperature and pulling speed were varied.

Filament winding of aramid/PA6 commingled yarns with in situ consolidation

2017 ◽  
Vol 31 (4) ◽  
pp. 465-482 ◽  
Author(s):  
Joanna CH Wong ◽  
Javier Molina Blanco ◽  
Paolo Ermanni
Keyword(s):  
Experimental Investigation ◽  
Polyamide 6 ◽  
Processing Parameters ◽  
Filament Winding ◽  
Void Content ◽  
Compression Moulding ◽  
Compaction Force ◽  
Commingled Yarns ◽  
Filament Winding Process

The in situ consolidation of commingled yarns during filament winding is demonstrated on an aramid fibre-reinforced polyamide 6 material. This article is a systematic experimental investigation of the filament winding processing parameters, namely, the heat gun temperature, line speed, fibre tension, compaction force and preheater temperature. Optimizing the processing parameters in this filament winding process produced a fully consolidated material with a void content of ∼0.25% which is comparable to the material quality achieved by means of compression moulding using the same intermediate materials.

scholarly journals High Bending Strength Hypereutectic Al-22Si-0.2Fe-0.1Cu-Re Alloy Fabricated by Selective Laser Melting

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 528
Author(s):  
Chunyue Yin ◽  
Zhehao Lu ◽  
Xianshun Wei ◽  
Biao Yan ◽  
Pengfei Yan
Keyword(s):  
Selective Laser Melting ◽  
Bending Strength ◽  
Primary Silicon ◽  
Processing Parameters ◽  
Powder Materials ◽  
Laser Melting ◽  
Maximum Value ◽  
Fine Microstructure ◽  
Average Size ◽  
Al Matrix

The objective of the study is to investigate the corresponding microstructure and mechanical properties, especially bending strength, of the hypereutectic Al-Si alloy processed by selective laser melting (SLM). Almost dense Al-22Si-0.2Fe-0.1Cu-Re alloy is fabricated from a novel type of powder materials with optimized processing parameters. Phase analysis of such Al-22Si-0.2Fe-0.1Cu-Re alloy shows that the solubility of Si in Al matrix increases significantly. The fine microstructure can be observed, divided into three zones: fine zones, coarse zones, and heat-affected zones (HAZs). Fine zones are directly generated from the liquid phase with the characteristic of petaloid structures and bulk Al-Si eutectic. Due to the fine microstructure induced by the rapid cooling rate of SLM, the primary silicon presents a minimum average size of ~0.5 μm in fine zones, significantly smaller than that in the conventional produced hypereutectic samples. Moreover, the maximum value of Vickers hardness reaches ~170 HV0.2, and bending strength increases to 687.70 MPa for the as-built Al-22Si-0.2Fe-0.1Cu-Re alloys parts, which is much higher than that of cast counterparts. The formation mechanism of this fine microstructure and the enhancement reasons of bending strength are also discussed.

scholarly journals Influence of Gradual Damage on the Structural Dynamic Behaviour of Composite Rotors: Experimental Investigations

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2421 ◽  
Author(s):  
Angelos Filippatos ◽  
Maik Gude
Keyword(s):  
Mechanical Properties ◽  
Composite Structures ◽  
Dynamic Behaviour ◽  
Experimental Investigations ◽  
Catastrophic Failure ◽  
Structural Dynamic ◽  
Delamination Growth ◽  
Reinforced Composite ◽  
Out Of Plane ◽  
Effective Mechanical Properties

Fibre-reinforced composite structures subjected to complex loads exhibit gradual damage behaviour with the degradation of the effective mechanical properties and changes in their structural dynamic behaviour. Damage manifests itself as a spatial increase in inter-fibre failure and delamination growth, resulting in local changes in stiffness. These changes affect not only the residual strength but, more importantly, the structural dynamic behaviour. In the case of composite rotors, this can lead to catastrophic failure if an eigenfrequency coincides with the rotational speed. The description and analysis of the gradual damage behaviour of composite rotors, therefore, provide the fundamentals for a better understanding of unpredicted structural phenomena. The gradual damage behaviour of the example composite rotors and the resulting damage-dependent dynamic behaviour were experimentally investigated under propagating damage caused by a combination of out-of-plane and in-plane loads. A novel observation is the finding that a monotonic increase in damage results in a non-monotonic frequency shift of a significant number of eigenfrequencies.

Optimization of investment casting parameters for reduction of shrinkage porosity in nickel-based superalloy castings by Taguchi method

2021 ◽  
pp. 2150136
Author(s):  
Peng Zhang ◽  
Guohuai Liu ◽  
Ye Wang ◽  
Shiping Wu ◽  
Zhaodong Wang
Keyword(s):  
Taguchi Method ◽  
Investment Casting ◽  
Signal To Noise Ratio ◽  
Casting Process ◽  
Processing Parameters ◽  
Shrinkage Porosity ◽  
Pouring Temperature ◽  
Nickel Based Superalloy ◽  
Preheating Temperature ◽  
Processing Optimization

In order to improve the castings quality of nickel-based superalloy in investment casting process, especially to reduce the shrinkage porosity, the processing parameters were optimized by numerical simulation and Taguchi method. The effects of processing parameters, such as pouring temperature, pouring time and mold shell preheating temperature, on the shrinkage porosity in the turbine nozzle investment castings prepared by K477 nickel-based superalloy were investigated. The results show that the effects of the mold shell preheating temperature, pouring temperature and pouring time are main influencing factors in turn, which are verified by the evaluation of signal-to-noise ratio and the analysis of variance. Further, based on the processing optimization, a K477 alloy turbine nozzle without shrinkage porosity was prepared with the optimized parameters: pouring temperature of 1450[Formula: see text]C, mold shell preheating temperature of 1050[Formula: see text]C and pouring time of 14 s, respectively.

scholarly journals Investigation into fibre orientation and weldline reduction of injection moulded short glass-fibre/polyamide 6-6 automotive components

2019 ◽  
Vol 33 (12) ◽  
pp. 1603-1628
Author(s):  
Sarah Mosey ◽  
Feras Korkees ◽  
Andrew Rees ◽  
Gethin Llewelyn
Keyword(s):  
Glass Fibre ◽  
Fibre Orientation ◽  
Weight Ratio ◽  
Polyamide 6 ◽  
Processing Parameters ◽  
Material Strength ◽  
Reinforced Polymers ◽  
Automotive Components ◽  
Glass Fibre Reinforced ◽  
Component Failures

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.

scholarly journals PIP Preparation of Silica Fibre Fabric Reinforced Silicon Nitride-Based Composites using Polyhydridomethylsilazane

2005 ◽  
Vol 14 (4) ◽  
pp. 096369350501400
Author(s):  
Gong-jin Qi ◽  
Chang-rui Zhang ◽  
Hai-feng Hu ◽  
Chang-cheng Zhou
Keyword(s):  
Mechanical Property ◽  
Silicon Nitride ◽  
Three Dimensional ◽  
Matrix Interface ◽  
Interface Bonding ◽  
Pull Out ◽  
New Type ◽  
Ammonia Atmosphere ◽  
Fibre Matrix ◽  
Silica Fibre

A new type of composites, three-dimensional silica fibre fabric reinforced silicon nitride-based composites, were prepared by PIP method through repeated infiltration of polyhydridomethylsilazane and pyrolysis at 773-873K in ammonia atmosphere. The density of the composites reached 1.66g/cm3 after four PIP cycles, and the flexural strength was 56.3 MPa. The composites showed a near-brittle fracture mode without long fibre pull-out in the fracture surface. It was the relatively strong fibre/matrix interface bonding that led to the moderate mechanical property.

Charaterization and Preparation of PA6/EPDM-g-MAH/OMMT Polymer Alloys Nanocomposites

2020 ◽  
Vol 852 ◽  
pp. 80-88
Author(s):  
Huan Peng Liu ◽  
Pei Yao Li ◽  
Zheng Gu ◽  
Li Wang ◽  
Guo Jun Song
Keyword(s):  
Mechanical Properties ◽  
Thermal Resistance ◽  
Bending Strength ◽  
Polyamide 6 ◽  
Ethylene Propylene Diene Monomer ◽  
Melt Extrusion ◽  
Heat Deflection Temperature ◽  
Notch Impact Strength ◽  
Application Prospects ◽  
Extrusion Method

The Polyamide 6 (PA6)/ maleic anhydride grafted ethylene-propylene-diene monomer (EPDM-g-MAH)/organic montmorillonite (OMMT) nanocomposites were successfully prepared by melt extrusion method at different contents of OMMT fillers. The content of OMMT were studied to discuss the mechanical properties, thermal resistance properties and melt-crystal behavior of the nanocomposites. The results were summarized as follows: The PA6/EPDM-g-MAH/OMMT nanocomposites were prepared using melt extrusion method. The influence of the OMMT filler contents on the properties of PA6/EPDM-g-MAH/OMMT nanocomposites were studied. The mechanical properties and thermal resistance properties were improved with the addition of OMMT. The results showed that when the content of OMMT was 3.5wt%, comparing to the pure PA6, the bending strength was improved 31.7%, the notch impact strength was improved by 40.5%, and the heat deflection temperature was improved by 31.1°C. This kind of nanocomposites had good application prospects.

Thermal Performance Measurement for Confined Heat Sinks by Using a Modified Transient Liquid Crystal Technique

2003 ◽  
Author(s):  
S. T. Kuo ◽  
M. P. Wang ◽  
M. C. Wu ◽  
Y. H. Hung
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Heat Sink ◽  
Heat Sinks ◽  
Experimental Investigations ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Preheating Temperature ◽  
Parametric Studies

A series of experimental investigations with a new modified transient liquid crystal method on the studies related to the fluid flow and heat transfer characteristics in a channel installed with a heat sink have been successfully performed. The parametric studies on the local and average effective heat transfer characteristics for confined heat sinks have been explored. The influencing parameters and conditions include air preheating temperature at channel inlet, flow velocity and heat sink types. Besides, a concept of the amount of enhanced heat transfer (AEHT) is introduced and defined as the ratio of j/f. The j/f ratio is almost independent of Reynolds number for a specific confined heat sink. The j/f ratios are 0.0603 and 0.0124 for fully-confined and unconfined heat sinks, respectively.

Study on the Forming Accuracy and Density of Eucalyptus/PES Fabricated by Laser Sintering

2015 ◽  
Vol 667 ◽  
pp. 200-205
Author(s):  
Yan Ling Guo ◽  
Yue Qiang Yu ◽  
Kai Yi Jiang
Keyword(s):  
Layer Thickness ◽  
Laser Power ◽  
Dimensional Accuracy ◽  
Processing Parameters ◽  
Variable Density ◽  
Laser Sintering ◽  
Powder Size ◽  
Forming Accuracy ◽  
Preheating Temperature ◽  
Forming Precision

. Based on orthogonal test, the forming accuracy and density of laser sintering eucalyptus/PES blend is studied in this paper. It mainly analysed the effect of the powder size and process parameters (such as laser power, layer thickness, preheating temperature, etc) on the forming precision and density of sintered eucalyptus/PES parts, also the correlation analysis of molding error caused by the powder’s physical properties and machine is performed. By measuring the parts’ dimensions, the results show that the laser power and powder size are two main factors influencing parts’ density, and variable density, layer thickness and preheating temperature jointly affect the dimensional accuracy. The optimized processing parameters are obtained. The powder size, laser power, scanning rate, layers thickness and preheating temperature are 300 mesh, 43W, 2000mm/s, 0.1mm, 60°C respectively.

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