scholarly journals Experimental Investigation of Wavy-Lap Bonds with Natural Cotton Fabric Reinforcement under Cyclic Loading

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2872
Author(s):  
Viktor Kolář ◽  
Miroslav Müller ◽  
Martin Tichý ◽  
Rajesh Kumar Mishra ◽  
Petr Hrabě ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cyclic Loading ◽  
Cotton Fabric ◽  
Mechanical Performance ◽  
Matrix Material ◽  
Safety Evaluation ◽  
Positive Influence ◽  
Sem Analysis ◽  
Adhesive Bonds ◽  
Fabric Surface

This study is focused on the mechanical properties and service life (safety) evaluation of hybrid adhesive bonds with shaped overlapping geometry (wavy-lap) and 100% natural cotton fabric used as reinforcement under cyclic loading using various intensities. Cyclic loading were implemented between 5–50% (267–2674 N) and 5–70% (267–3743 N) from the maximum strength (5347 N) measured by static tensile test. The adhesive bonds were loaded by 1000 cycles. The test results demonstrated a positive influence of the used reinforcement on the mechanical properties, especially during the cyclic loading. The adhesive bonds Tera-Flat withstood the cyclic load intensity from 5–70% (267–3743 N). The shaped overlapping geometry (wavy-lap bond) did not have any positive influence on the mechanical performance, and only the composite adhesive bonds Erik-WH1 and Tera-WH1 withstood the complete 1000 cycles with cyclic loading values between 5–50% (267–2674 N). The SEM analysis results demonstrated a positive influence on the fabric surface by treatment with 10% NaOH aqueous solution. The unwanted compounds (lignin) were removed. Furthermore, a good wettability has been demonstrated by the bonded matrix material. The SEM analysis also demonstrated micro-cracks formation, with subsequent delamination of the matrix/reinforcement interface caused by cyclic loading. The experimental research was conducted for the analysis of hybrid adhesive bonds using curved/wavy overlapping during both static and cyclic loading.

Mechanical Performance and Fracture Behavior of Recycled AA6061-T6 Alloy Melted from Aluminium Chips

2017 ◽  
Vol 7 (1) ◽  
pp. 1-17
Author(s):  
Naveed Akhtar ◽  
Razzaq Ahmed ◽  
Muhammad Arfan ◽  
Muhammad Noshad Ali
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Compounds ◽  
Fracture Behavior ◽  
Mechanical Performance ◽  
Sem Analysis ◽  
Reverberatory Furnace ◽  
Molten Bath ◽  
Furnace Charge ◽  
Mixed Nature

Aluminium chips were re-melted under the molten bath in a gas fired reverberatory furnace and superior quality recycled AA6061-T6 alloy was synthesized. The chips were added 5 to 20% by weight in the recycled alloy. The furnace charge included clean scrap of the same alloy (AA6061) along with the machining chips or tunings of mixed nature. The chips used in this study were mostly generated from lath/bore operations carried on homogenized billets. The fabricated alloy of each heat was characterized for microstructures, mechanical properties and fracture behavior. The results showed that the metallurgical and mechanical performance of the recycled alloy was comparable to the primary alloy. However, SEM analysis of the recycled alloy revealed a sizeable amount of Fe and Si containing intermetallic compounds such as AlFeSi, AlFeMg, and AlSiMg phases.

scholarly journals Quasi-Static Tests of Hybrid Adhesive Bonds Based on Biological Reinforcement in the Form of Eggshell Microparticles

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1391 ◽  
Author(s):  
Viktor Kolář ◽  
Miroslav Müller ◽  
Rajesh Mishra ◽  
Anna Rudawska ◽  
Vladimír Šleger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cyclic Loading ◽  
Service Life ◽  
Adhesive Layer ◽  
Maximum Load ◽  
Adhesive Bonds ◽  
Static Tests ◽  
Static Test ◽  
The Matrix ◽  
Positive Effect

The paper is focused on the research of the cyclic loading of hybrid adhesive bonds based on eggshell microparticles in polymer composite. The aim of the research was to characterize the behavior of hybrid adhesive bonds with composite adhesive layer in quasi-static tests. An epoxy resin was used as the matrix and microparticles of eggshells were used as the filler. The adhesive bonds were exposed to cyclic loading and their service life and mechanical properties were evaluated. Testing was performed by 1000 cycles at 5–30% (165–989 N) and 5–70% (165–2307 N) of the maximum load of the filler-free bond in the static test. The results of the research show the importance of cyclic loading on the service life and mechanical properties of adhesive bonds. Quasi-static tests demonstrated significant differences between measured intervals of cyclic loading. All adhesive bonds resisted 1000 cycles of the quasi-static test with an interval loading 5–30%. The number of completed quasi-static tests with the interval loading 5–70% was significantly lower. The filler positively influenced the service life of adhesive bonds at a higher amount of quasi-static tests, i.e., the safety of adhesive bonds increased. The filler had a positive effect on adhesive bonds ABF2, where the strength significantly increased up to 20.26% at the loading of 5–30% against adhesive bonds ABF0. A viscoelasticity characteristic (creep) of the adhesive layer occurred at higher values of loading, i.e., between loading 5–70%. The viscoelasticity behavior did not occur at lower values of loading, i.e., between loading 5–30%.

Characterization of discontinuous carbon fiber liquid molded PA-6 composites via strategic placement of additional reinforcements

2018 ◽  
Vol 37 (22) ◽  
pp. 1335-1345 ◽  
Author(s):  
Siddhartha Brahma ◽  
Vikas Patel ◽  
Selvum Pillay ◽  
Haibin Ning ◽  
Vinoy Thomas
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Surface Area ◽  
Mechanical Characterization ◽  
Mechanical Performance ◽  
Total Surface Area ◽  
Sem Analysis ◽  
Average Increase ◽  
Similar Increase

The flexibility of processing PA6-based discontinuous carbon fiber panels using vacuum-assisted resin transfer molding was studied. The ease of incorporating various reinforcements namely baseline, tow in the center of preform, fabric in the center of preform and fabric on the outside as skin was investigated. Mechanical characterization was conducted on all the variations made. There was an average increase of about 3%, 20% and 47% in the tensile properties of tow in the center, fabric in the center and fabric on the outside as skin, respectively, as compared to the baseline. A similar increase in properties was noticed in its flexural and impact strength. The data showed a correlation between the mechanical properties and the total surface area of additional reinforcements used. As the surface area of the reinforcement increased, the mechanical properties increased as well. It also showed that reinforcements on the surface of the preform as a skin performed the best. DMA analysis showed the effect of reinforcement on the storage modulus and tan delta across temperatures ranging from 30°C to 150°C. SEM analysis showed that the fibers and the additional reinforcements were coated with PA6 which translated into consistent mechanical performance.

scholarly journals Impact of Wetting and Drying Cycles on the Mechanical Properties and Microstructure of Vegetation-growing Concrete

2021 ◽  
Vol 20 (4) ◽  
Author(s):  
Xiaole Huang ◽  
Wennian Xu ◽  
Yu Ding ◽  
Dong Xia ◽  
Shiyuan Xiong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Structural Damage ◽  
Mechanical Performance ◽  
Sem Analysis ◽  
Influential Factors ◽  
Linear Functions ◽  
Experimental Program ◽  
Widespread Application ◽  
Wetting And Drying ◽  
Wetting And Drying Cycles

Vegetation-growing Concrete (VC), as a new type of cemented soil, is usually used for plants growing on the surface of high and steep rocky slopes. With the widespread application of VC substrate, a pressing problem arises to ensure its durability under wetting and drying conditions. To explore the greatest possible impact on the mechanical properties and microstructure features of VC substrate, an experimental program including triaxial test, SEM analysis, and ultrasonic testing was implemented. The results showed that wetting and drying cycles can significantly decrease more than 40-percent of peak strength, 60-percent of residual strength, and 50-percent of cohesion for VC substrate under ultimate conditions. The fundamental cause of reduction in mechanical performance was found to be the weakening of the bond between soil particles. And it was discovered that structural damage increased as the number of wetting and drying cycles increased but at a slower rate. Based on the tested results, linear functions between the loss extent parameters of mechanical performance and the structural damage variable were established for the VC substrate. Finally, the action mechanisms of wetting and drying cycles for VC substrate were discussed, and the main influential factors were proposed.

Enhanced Durability of Graphene-Based Epoxy Films

2019 ◽  
Vol 813 ◽  
pp. 279-284
Author(s):  
Carlo Naddeo ◽  
Liberata Guadagno ◽  
Roberto Pantani ◽  
Vito Speranza ◽  
Annalisa Acquesta ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Beneficial Effect ◽  
Morphological Feature ◽  
Mechanical Performance ◽  
Oxidative Degradation ◽  
Film Surface ◽  
Sem Analysis ◽  
Polymeric Films ◽  
Strong Decrease ◽  
Nanoscale Level

Graphene-based nanoparticles are suitable to enhance toughness related to impact, fracture and fatigue of epoxy nanocomposites to make them able to meet industrial requirements. The increase in the mechanical performance of graphene-based films is well known in the literature. This paper highlights an additional beneficial effect of graphene-based nanoparticles, which is related to the increase of the photooxidative resistance of polymeric films. Graphene Nanoplatelets (GNPs) have been incorporated, at different weight percentages, in the epoxy films. Unfilled and nanofilled films (30 ± 1.5 μm thick) have been subjected to the accelerated photo-oxidative degradation by exposing them to UV-A radiation (295–380 nm). AFM-Harmonix modulus maps at the micro and nanoscale level have been detected to investigate the effect of graphene nanoparticle on the mechanical properties of untreated and UV treated unfilled and nanofilled samples. SEM analysis has been used to analyse the effect of graphene on morphological features of the film surface. UV irradiation determines relevant damages of the mechanical properties and morphological feature of the unfilled sample. The experiments carried out on the nanofilled films show that GNPs, dispersed in the epoxy-based films, determine a strong decrease in the entity of the damages of the film surfaces.

Incorporation of Hybrid Pre-Dispersed Organo-Montmorillonite/ Destabilized Bentonite Nanofillers for Improving Tensile Strength of PEVA Copolymer with 40% Vinyl Acetate Composition

2020 ◽  
Vol 1010 ◽  
pp. 118-123
Author(s):  
Tuty Fareyhynn Mohammed Fitri ◽  
Azlin Fazlina Osman ◽  
Rahimah Othman ◽  
Zaleha Mustafa
Keyword(s):  
Tensile Strength ◽  
Vinyl Acetate ◽  
Mechanical Performance ◽  
Matrix Material ◽  
Tensile Load ◽  
Sem Analysis ◽  
Hybrid Nanocomposite ◽  
Elongation At Break ◽  
Melt Compounding ◽  
Poly Ethylene

In this work, soft and flexible poly (ethylene-co-vinyl acetate) (PEVA) with 40% vinyl acetate (VA) composition was used as matrix material to form nanocomposites with single nanofiller (organo-montmorillonite (OMMT) or Bentonite (Bent)) and hybrid nanofillers (OMMT+Bent in the ratios of 4:1, 3:2, 2:3 and 1:4). In order to achieve greater exfoliation and dispersion of the hybrid nanofillers in the PEVA matrix, the pre- dispersing and destabilization technique was applied to the O-MMT and Bent, respectively. The procedures were done prior to the melt compounding process of the nanocomposite. A tensile test was done to evaluate the mechanical properties of the resultant nanocomposites and to allow the selection of the best OMMT/Bent ratio for the production of the hybrid nanocomposite. The structure and fractured surfaces of the neat PEVA and nanocomposite were analyzed using Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM), respectively. Results indicated that the addition of hybrid pre-dispersed OMMT/destabilized bentonite nanofillers into the PEVA matrix resulted in greater mechanical performance as compared to the single OMMT or single Bent nanofiller. The best achievement in the tensile strength and elongation at break of the PEVA hybrid nanocomposite was obtained when the hybrid nanofillers was added in the ratio of 4:1 (OMMT: Bent). The SEM analysis showed that the PEVA hybrid nanocomposite with 4OMMT: 1Bent had greater matrix deformation than the neat PEVA when subjected to tensile load. This mechanical deformation could be related to the increased flexibility of the PEVA chains which facilitated more energy absorption during the stretching of the material. Apparently, this mechanism acted as a matrix toughening process which allowed the increment of both tensile strength and elongation at break values of the PEVA upon the addition of the hybrid nanofillers.

scholarly journals Viscoelastic Behavior of Glass-Fiber-Reinforced Silicone Composites Exposed to Cyclic Loading

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1862 ◽  
Author(s):  
Julia Beter ◽  
Bernd Schrittesser ◽  
Bernhard Lechner ◽  
Mohammad Reza Mansouri ◽  
Claudia Marano ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Fiber Orientation ◽  
Mechanical Performance ◽  
Glass Fibers ◽  
Matrix Material ◽  
Viscoelastic Behavior ◽  
Fiber Reinforced ◽  
Step Cycle ◽  
Dynamic Mechanical

The aim of this work was to analyze the influence of fibers on the mechanical behavior of fiber-reinforced elastomers under cyclic loading. Thus, the focus was on the characterization of structure–property interactions, in particular the dynamic mechanical and viscoelastic behavior. Endless twill-woven glass fibers were chosen as the reinforcement, along with silicone as the matrix material. For the characterization of the flexible composites, a novel testing device was developed. Apart from the conventional dynamic mechanical analysis, in which the effect of the fiber orientation was also considered, modified step cycle tests were conducted under tensile loading. The material viscoelastic behavior was studied, evaluating both the stress relaxation response and the capability of the material to dissipate energy under straining. The effects of the displacement rate of the strain level, the amplitude of the strain applied in the loading–unloading step cycle test, and the number of the applied cycles were evaluated. The results revealed that an optimized fiber orientation leads to 30-fold enhanced stiffness, along with 10 times higher bearable stress. The findings demonstrated that tailored reinforced elastomers with endless fibers have a strong influence on the mechanical performance, affecting the structural properties significantly.

Microstructure and Mechanical Properties of AISI 8620 Steel Processed by ECAP

2014 ◽  
Vol 1611 ◽  
pp. 89-94
Author(s):  
Diana M. Marulanda ◽  
Jair G. Cortés ◽  
Marco A. Pérez ◽  
Gabriel García
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Equivalent Strain ◽  
Sem Analysis ◽  
Structure Evolution ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
X Ray ◽  
Angular Pressing ◽  
Before And After

ABSTRACTThe aim of this work is to process by equal channel angular pressing (ECAP) a low carbon – triple-alloyed steel containing 0.2% C, 0.5% Cr, 0.6% Ni, 0.2% Mo and 0.8 Mo. The process is performed at room temperature for up to four passes using route Bc with an equivalent strain of ∼0.6 after a single pass. Structure evolution before and after deformation is studied using scanning electron microscopy (SEM) and x-ray diffraction (XRD) and mechanical properties are assessed by microhardness and tensile testing. A significant improvement of the mechanical properties is found with increasing number of ECAP passes. Micro-hardness increases from 216 HV for the initial sample to 302 HV after four passes and tensile strength increases to 1200 MPa compared with 430 MPa prior to ECAP. X-ray diffraction and SEM analysis show changes in the original ferritic-perlitic structure through ferrite grain refinement and the deformation of perlite. This nickel-chromium-molybdenum alloy is used in manufacturing as gear material, and when it is hardened and formed through carburizing or boronizing it can be used to make hard-wearing machine parts. However, the ECAP process has not been used to harden this steel and to change its structure to obtain better mechanical performance.

scholarly journals Influence of Nano Silica Particles on Durability of Flax Fabric Reinforced Geopolymer Composites

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1459 ◽  
Author(s):  
Hasan Assaedi ◽  
Thamer Alomayri ◽  
Faiz Shaikh ◽  
It-Meng Low
Keyword(s):  
Mechanical Properties ◽  
Ambient Temperature ◽  
Mechanical Performance ◽  
Physical And Mechanical Properties ◽  
Positive Influence ◽  
Silica Particles ◽  
Natural Fibres ◽  
Nano Silica ◽  
Flax Fibres ◽  
Geopolymer Composites

The durability of natural fibres as reinforcement in geopolymer composites continues to be a matter of concern due to the alkalinity of activators of geopolymer matrices. The alkaline environment is the main reason for natural fibres degradation in cementitious matrices. This paper presents the influence of nano silica (NS) on the durability and mechanical performance of geopolymer composites that are reinforced with flax fabric (FF). The durability investigations were conducted after the storage of samples at ambient temperature for 32 weeks. The study revealed that the addition of nano silica has a positive influence on the physical and mechanical properties of these composites. The presence of NS accelerated the geopolymeric reaction and lowered the alkalinity of the system, thus reducing the degradation of flax fibres.

Weldability - Behavior of Welded Reinforcement

2019 ◽  
Vol 70 (10) ◽  
pp. 3469-3472
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Mechanical Characteristics ◽  
Mechanical Performance ◽  
Current Work ◽  
Carbon Equivalent ◽  
Work Process ◽  
Ultimate Limit

Weldability involves two aspects: welding behavior of components and safety in operation. The two aspects will be reduced to the mechanical characteristics of the elements and to the chemical composition. In the case of steel reinforcing rebar’s, it is reduces to the percentage of Cech(carbon equivalent) and to the mechanical characteristics: the yielding limit, the ultimate limit, and the elongations which after that represent the ductility class in which the re-bars is framed. The paper will present some types of steel reinforcing rebar’s with its mechanical characteristics and the welding behavior of those elements. In the current work, process-related behavior of welded reinforcement, joint local and global mechanical properties, and their correlation with behavior of normal reinforcement and also the mechanical performance resulted in this type of joints. Keywords: welding behavior, ultimate limit, reinforcing rebar’s

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