scholarly journals Influence of Thermal Shocks on Residual Static Strength, Impact Strength and Elasticity of Polymer-Composite Materials Used in Firefighting Helmets

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 57
Author(s):  
Daniel Pieniak ◽  
Agata Walczak ◽  
Marcin Oszust ◽  
Krzysztof Przystupa ◽  
Renata Kamocka-Bronisz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Glass Fiber ◽  
Elastic Properties ◽  
Polymer Composite ◽  
Experimental Studies ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced ◽  
The Impact ◽  
Thermal Shocks

The article presents results of experimental studies on mechanical properties of the polymer-composite material used in manufacturing firefighting helmets. Conducted studies included static and impact strength tests, as well as a shock absorption test of glass fiber-reinforced polyamide 66 (PA66) samples and firefighting helmets. Samples were subject to the impact of thermal shocks before or during being placed under a mechanical load. A significant influence of thermal shocks on mechanical properties of glass fiber-reinforced PA66 was shown. The decrease in strength and elastic properties after cyclic heat shocks ranged from a few to several dozen percent. The average bending strength and modulus during the 170 degree Celsius shock dropped to several dozen percent from the room temperature strength. Under these thermal conditions, the impact strength was lost, and the lateral deflection of the helmet shells increased by approximately 300%. Moreover, while forcing a thermal shock occurring during the heat load, it was noticed that the character of a composite damage changes from the elasto-brittle type into the elasto-plastic one. It was also proved that changes in mechanical and elastic properties of the material used in a helmet shell can affect the protective abilities of a helmet.

Effects of the Self-Healing Microcapsules on the Impact Property of Polymer Composite Gear

2011 ◽  
Vol 66-68 ◽  
pp. 683-687 ◽  
Author(s):  
Li Zhang ◽  
Yan Jue Gong ◽  
Shuo Zhang
Keyword(s):  
Glass Fiber ◽  
Polymer Composite ◽  
The Self ◽  
Impact Property ◽  
Self Healing ◽  
Fiber Reinforced ◽  
Mechanical Impact ◽  
Glass Fiber Reinforced ◽  
The Impact

By designing the different formulations of the composites and adopting optimized technology including extrusion and molding, the effects of the Micro-capsules on the properties of nylon composites are analyzed by the impact property test. The mechanical impact property of the glass fiber reinforced nylon composites is influenced little if the content of the self-healing microcapsules added is less than 3.5%, and the technology of self-healing microcapsules used in the polymer composite gear is feasible.

scholarly journals Experimental investigation and Analysis on effect of fiber orientation on mechanical properties of synthetic and natural fiber reinforced hybrid composite

2021 ◽  
Author(s):  
Pradeep Devaenthiran ◽  
◽  
Kumar Murugesan ◽  
Sangaravadivel Palaniappan ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Impact Analysis ◽  
Natural Fiber ◽  
Impact Load ◽  
Material Selection ◽  
Hybrid Composites ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced ◽  
The Impact

Automobile bumper is an essential component that is commonly used to absorb the impact load during vehicle collisions, in fact it saves lives at such occurrences.In order to withstand the impact load, and the bumper deforms itself during collision and protects the passengers by havingthe proper cross section and the material selection. In this way, the study explores the mechanical characterization of fabricated composite and its structural analysis. Impact conditions have to be studied for improving the mechanical properties of the bumper during collision. The material chosen for analysis is jute and Glass fiber reinforced hybrid epoxy composite, considering its light weight and strength characteristics. Composites with two different fibre orientations (45°/90°) are fabricated using Hydraulic Compression Moulding technique. From experimental observations of jute and glass fiber reinforced hybrid composites, the orientation has significant effect on the structural and mechanical properties. The results are validated using the simulation of a bumper by impact modelling using CATIA software and impact analysis is carried out using ANSYS.

The influence of incorporation of silica and carbon nanoparticles on the mechanical properties of hybrid glass fiber reinforced epoxy

2018 ◽  
Vol 49 (2) ◽  
pp. 181-199 ◽  
Author(s):  
M Megahed ◽  
AA Megahed ◽  
MA Agwa
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Glass Fiber ◽  
Tensile Properties ◽  
Hybrid Composites ◽  
Fatigue Performance ◽  
Hybrid Nanocomposites ◽  
Fiber Reinforced ◽  
Sem Images ◽  
Glass Fiber Reinforced

Recently, the study of hybrid nanocomposites has attracted much attention because they are highly expected for being used in many applications. In this context, there is an insisting need to investigate the effect of incorporation of silica and carbon particulates nanofillers into epoxy reinforced with woven and nonwoven tissue glass fiber. The influence of incorporation of silica (SiO2) and carbon black nanoparticles (C) with different weight fractions on the tensile properties, impact strength and fatigue performance of epoxy matrix reinforced with two types of E-glass fiber was investigated. The results showed an improvement in tensile properties, impact strength and fatigue life with addition of almost all nanoparticles contents considerably with respect to that of the neat glass fiber reinforced epoxy composites (NGFRE). Hybrid composites filled with 0.5 wt.% C exhibited the highest tensile strength and fatigue performance with an enhancement of 19% and 60% compared to NGFRE, respectively. An increase of 57% and 28% in tensile modulus and impact strength over NGFRE was obtained respectively with hybrid composites filled with 1 wt.% C. Adding 0.25 wt.% SiO2 and 0.25 wt.% C simultaneously showed an improvement in mechanical properties. SEM images of tensile and impact fracture surfaces are presented for CS 0.5 specimens which in turn reveal weak fiber/matrix interface.

scholarly journals Mechanical behavior of transparent fiber reinforced polyester composites at extreme temperatures

2018 ◽  
Author(s):  
◽  
Saad Ramadhan Ahmed
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Polyester Resin ◽  
Unsaturated Polyester ◽  
Glass Fibers ◽  
Fiber Reinforced Polymers ◽  
Extreme Conditions ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced ◽  
The Impact

Selecting materials for harsh or extreme environmental conditions can be a challenge. The combination of a harsh environment, large forces over extended periods and the need for lowest possible cost restricts the choice of materials. One potential material is glass fiber reinforced polymers that are widely used in structural systems as load bearing elements, they are relatively low cost and can be tailored to achieve a range of mechanical properties. This investigation presents the preparation of transparent glass fiber reinforced unsaturated polyester composite and the evaluation of its optical and mechanical properties under extreme conditions of temperature. The polyester resin was reinforced with E-glass fibers to manufacture a composite using the hand layup method. Transparency was achieved by modifying the refractive index of the polyester resin to match that of the glass fibers. This investigation also presents the evaluation of glass fiber reinforced unsaturated polyester under quasi-static tension loading and puncture testing using a drop weight at extreme conditions. The results showed that the reinforced composite had a higher fracture stress and chord modulus at all temperatures ranging from +60 [degree]C to -80 [degree]C as compared to the unreinforced polyester matrix. The unreinforced polyester has a higher stiffness at lower temperatures due to reduced polymer chain mobility and higher clamping pressure of the matrix on the glass fiber reinforcement. The damage created by the impact reduces with decreasing temperatures, while the energy absorb remains constant with temperature.

Analysis of impacts of thermal shocks on mechanical properties of E-glass fiber reinforced polyester composites

2021 ◽  
pp. 002199832110176
Author(s):  
Zahra Jamshidi ◽  
Sayyed Mahdi Hejazi ◽  
Mohammad Sheikhzadeh ◽  
Azam Alirezazadeh
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Glass Fiber ◽  
Woven Fabric ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced ◽  
Wide Range ◽  
Fiber Deformation ◽  
Polyester Composites ◽  
Thermal Shocks

Glass fiber reinforced polyester composites are economic and high-performance composite materialsthat has gained a wide range of applications. Besides the developments in composites design, scientific studies addressing the consequences of thermal changes on the mechanical properties of fiber reinforced polymer composites(FRPCs) are scarce. Therefore, the main aim of the present work is to investigate the physical/mechanical properties of glass fiber reinforced polyester composites under thermal shocks. The effects of thermal cycle duration (2, 5 and 20 hours) on the porosity and mechanical properties (maximum stress, strain, elastic modulus and impact resistance) of polymeric composites reinforced by glass fiber, woven fabric and copper/silica nanoparticles (NPs) were investigated. The results exhibited that the porosity and mechanical properties changed obviously in long duration cycles, i.e., 20 hours. Major reduction trends were observed when the fabric reinforced samples were further reinforced by NPs. It was concluded that although NPs reduce porosity and pose filling effect in composite matrix, can also provide stress concentration locations. The composites reinforced by woven fabric and prepared by RTM method provide better mechanical properties. Moreover, after thermal shocks, the fibers within the composite structure formed curved shapes. Consequently, a reduction occurred at the elastic modulus of fibrous reinforced composites (fiber or fabric) after thermal cycles. Besides theelevated porositywas the predominant factor reducing elastic modulus, fiber deformation was also considered as a hidden factor which has never been discussed in previous research studies. A model of bicomponent structure was used to explain the effects of fiber deformation on elastic modulus of the FRPCs.

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