Accelerated weathering effects on mechanical, thermal and viscoelastic properties of kenaf/pineapple biocomposite laminates for load bearing structural applications

2021 ◽  
pp. 51465
Author(s):  
Santosh Kumar ◽  
Abir Saha ◽  
Sumit Bhowmik
Keyword(s):  
Viscoelastic Properties ◽  
Accelerated Weathering ◽  
Load Bearing ◽  
Structural Applications ◽  
Weathering Effects

Effect of layering pattern and fiber hybridization on viscoelastic properties of PALF/COIR hybrid epoxy composites

2021 ◽  
Vol 15 (1) ◽  
pp. 7894-7906
Author(s):  
Mohit Mittal ◽  
Rajiv Chaudhary
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Viscoelastic Properties ◽  
Volume Fraction ◽  
Interfacial Region ◽  
Damping Factor ◽  
Structural Applications ◽  
Fiber Matrix ◽  
Hybrid Biocomposite

To design and develop a hybrid biocomposite material for structural applications, it becomes necessary to determine the optimum fibers layering pattern. Therefore, in this research work, the different layered hybrid biocomposite boards i.e. bilayer pineapple/coir (P/C), trilayer (PCP, CPC), and intimately mixed (IM) were developed and characterized for viscoelastic properties. The composites were made by hand lay-up method, keeping the volume ratio of PALF and COIR 1:1 and the total fiber volume fraction is 0.40 volume of composite. Dynamic mechanical thermal analysis test was employed to characterize the viscoelastic behavior in terms of storage modulus, loss modulus, loss damping factor, and the glass transition temperature. Amongst all the different layered hybrid composites, the trilayer CPC has lowest value (0.635) of effectiveness coefficient with highest stiffness and activation energy (40.54 kJ/mole). It confirms the better fiber-matrix interaction at the interfacial region. The glass transition temperature of CF-EP and PF-EP was increased by 8.74% and 13.15% respectively by the synergistic hybridization of cellulosic fibers. The PCP layered composite possesses lowest value of phase transition energy (9.17 kJ/mole) and this was because of the poor fiber-matrix interfacial adhesion.

Thermoplastics: New Opportunities for Mechanics

1986 ◽  
Vol 39 (11) ◽  
pp. 1697-1703 ◽  
Author(s):  
Vijay K. Stokes
Keyword(s):  
Polymeric Materials ◽  
Thermoplastic Resin ◽  
Research Directions ◽  
Load Bearing ◽  
Structural Applications ◽  
New Research

The use of thermoplastic polymeric materials in structural applications is increasing. A good example is the all-plastic thermoplastic automotive bumper, made of unfilled nonreinforced thermoplastic resin, which is capable of withstanding an 8 kmph (5 mph) impact. The structural applications of such materials are expected to grow dramatically. These materials behave very differently from metals, and their use in load-bearing applications raises interesting mechanics issues that need to be addressed. This paper discusses some opportunities for new research directions in mechanics, which would impact the use of plastics in load-bearing applications.

Characterization of structural adhesives for load-bearing composite structural applications

1994 ◽  
Vol 27 (1-2) ◽  
pp. 57-64 ◽  
Author(s):  
K.J. Ahn ◽  
Y.S. Eom ◽  
Y.T. Shim ◽  
J.C. Seferis
Keyword(s):  
Load Bearing ◽  
Structural Adhesives ◽  
Structural Applications

scholarly journals Viscoelastic properties of thermo-hydro-mechanically treated beech (Fagus sylvatica L.) determined using dynamic mechanical analysis

2020 ◽  
Author(s):  
Andreja Kutnar ◽  
Jane O’Dell ◽  
Christopher Hunt ◽  
Charles Frihart ◽  
Frederick Kamke ◽  
...  
Keyword(s):  
Cell Wall ◽  
Fagus Sylvatica ◽  
Viscoelastic Properties ◽  
Creep Compliance ◽  
Wood Products ◽  
Direct Result ◽  
Densified Wood ◽  
Dynamic Mechanical ◽  
Creep Stress ◽  
Structural Applications

AbstractThermo-hydro-mechanical (THM) processing can improve the intrinsic properties of wood, produce new materials, and give desired form and function to new applications. THM treatments change the mechanical properties of wood and may change its viscoelastic properties as well. Therefore, the objective of this study was to assess the viscoelastic properties of THM-treated wood at several humidity and load levels. To explore these changes, this study applied a THM treatment to beech (Fagus sylvatica L.) wood with steam (620 kPa) and heat (170 °C), followed by densification and increased temperature (200 °C) in a hot-press, which was then cooled while under pressure. Two initial specimen thicknesses before THM treatment were used to study the difference between density ratios. Specimens were tested in a humidity-controlled dynamic mechanical analyser (DMA) to apply creep stress with different loading levels (20% and 30% of expected modulus of rupture) and relative humidity levels (30%, 50%, and 65% RH). The creep compliance/recovery response was monitored, and dynamic moduli were measured before and after the application of creep stress. The loss modulus measured was highest for specimens tested at 65% RH and lowest in specimens tested at 30% RH, which is a direct result of the viscous response of the material. Increased damping of the specimens was also observed at higher RH, which is typical for wood products due to added moisture in the cell wall acting as a plasticizer to cell wall polymers. Like previous studies, THM treatment lowered the equilibrium moisture content (EMC) of densified wood specimens, which affected their mechanical performance. THM treatment yields higher strength and lower EMC, suggesting that this product could be suitable for structural applications where their service life is in an indoor environment. THM treatment also resulted in decreased creep compliance and recovery compliance as compared to control specimens.

scholarly journals The Efficiency of Utilisation of High-strength Steel in Tubular Profiles

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1193 ◽  
Author(s):  
Ieva Misiūnaitė ◽  
Viktor Gribniak ◽  
Arvydas Rimkus ◽  
Ronaldas Jakubovskis
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
High Strength Steel ◽  
Current Trend ◽  
Weight Ratio ◽  
High Strength ◽  
Beam Specimen ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Structural Applications

The use of high-strength steel (HSS) is a current trend of the construction industry. Tubular profiles are widely used in various structural applications because of their high stiffness-to-weight ratio, exceptional resistance to torsion, and aesthetic appearance. However, the increase of the strength for the same elastic modulus of the material and geometry of tubular profiles is often not proportional to the rise of the load-bearing capacity of the structural element. The obtained experimental results support the above inference. The study was based on the flexural test results of two groups of HSS and normal-strength steel (NSS) tubular specimens with a 100 × 100 × 4 mm (height × width × thickness) cross-section. Numerical (finite element) simulation results demonstrated that the shape of the cross-section influenced the efficiency of utilisation of HSS. The relationship between the relative increase of the load-bearing capacity of the beam specimen and the corresponding change of the steel strength determined the utilisation efficiency.

scholarly journals Effects of Accelerated Weathering on Degradation Behavior of Basalt Fiber Reinforced Polymer Nanocomposites

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2621
Author(s):  
Ummu Raihanah Hashim ◽  
Aidah Jumahat ◽  
Mohammad Jawaid ◽  
Rudi Dungani ◽  
Salman Alamery
Keyword(s):  
Water Absorption ◽  
Basalt Fiber ◽  
Fiber Reinforced Polymer ◽  
Uv Exposure ◽  
Flexural Properties ◽  
Accelerated Weathering ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Structural Applications ◽  
Basalt Fiber Reinforced Polymer

This work aims to give insight on the effect of accelerated weathering, i.e., the combination of ultraviolet (UV) exposure and water spraying, on the visual and mechanical properties of basalt fiber reinforced polymer (BFRP) composites. The solvent exchange method, sonication and high shear milling technique were used to prepare the nanocomposite laminates. Three types of laminates were fabricated, i.e., unmodified BFRP, nanosilica modified BFRP and graphene nanoplatelet (GNP) modified BFRP composites with the total fiber loading of 45 wt.%. Glass fiber reinforced polymer (GFRP) laminate was also prepared for performance comparison purposes between the natural and synthetic fibers. The laminates were exposed to UV with a total weathering condition of 504 h using a Quantum-UV accelerated weathering tester. The weathering condition cycle was set at 8 h 60 °C UV exposure and 4 h 50 °C condensation. The discoloration visual inspection on the tested specimen was observed under the optical microscope. The obtained results showed that the UV exposure and water absorption caused severe discoloration of the laminates due to photo-oxidation reaction. The effect of weathering conditions on tensile and flexural properties of unmodified BFRP composites indicated that the UV exposure and water absorption caused reduction by 12% in tensile strength and by 7% in flexural strength. It is also found that the reduction in tensile and flexural properties of nanomodified BFRP composites was smaller than the unmodified system. It concluded from this work, that the mineral based composites (i.e., BFRP) has high potential for structural applications owing to its better properties than synthetic based composites (i.e., GFRP).

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