Plastic is an amazing material, and wonderful invention, it has changed the world. Plastic is used everywhere and every day across the globe. But despite its varied uses, its disposal has threatened the environment. Biodegradable plastics can meet these needs and can easily be disposed to the environment. This work focuses on the characterization and performance analysis of starch bioplastics and composite bioplastic to reduce the plastic pollution by its various uses. TGA, DSC, SEM, FTIR, and surface roughness analyses were used to characterize, the mechanical properties, thermal properties and the morphology of the starch bioplastics and composite bioplastic. Starch bioplastics were fabricated using starch vinegar and glycerol. Composite bioplastics ware fabricated using starch, vinegar, glycerol and titanium dioxide. The addition of titanium dioxide improved the tensile strength of the bioplastics from 3.55 to 3.95 MPa and decreased elongation from 88% to 62%. According to Differential Scanning Calorimetry (DSC) Test, the melting point (T
m
) and Glass Transition Temperature (T
g
) significantly affected by the presence of titanium dioxide (TiO
2
). The degree of nano-composite crystallinity was formed by the strong interfacial interaction between the titanium dioxide nanoparticles and the amorphous region of the chain. The decomposition temperature of starch bioplastic was increased by mixing with titanium dioxide nanoparticles. The results gained from SEM showed that better compatible morphologies in composite bioplastic compared to starch bioplastic for its fewer voids, holes, and crack. The functional group O–H, C–H, C=O, and C–O indicate the formation of starch bioplastics and composite bioplastics has already occurred which was confirmed by FTIR spectroscopy. The result is also verified with the available results of other researchers. Therefore, composite bioplastic is a modified elevation of a starch bioplastic with a modified upgrade feature. It can be an alternative to existing conventional plastic, especially packaging applications.
Aluminium-based metal matrix composites play a significant role in the field of aerospace, automobile, structural, and military applications due to their enhanced mechanical and tribological properties that contrasted to monolithic materials. Severe metal service conditions, such as cutting, grinding, and drilling and demand tribological and mechanical properties, must be improved. Metal matrix composites (MMCs) reinforced with filler particles are covenant materials for rectifying these issues. This study experimentally investigated the effect of normal load and sliding velocity on the friction and wear properties of Al-6063-based MMC embedded with filler particles. Experiments were conducted under normal loads of 5 N, 7.5 N, and 10 N and velocities of 0.5 m/s, 1 m/s, and 1.5 m/s. The experimental results revealed controlling friction and wear rate of aluminium-based MMC. The friction coefficient and wear resistance were improved by the aluminium-based MMC. The morphology of the metal matrix composites was analysed through scanning electron microscopy (SEM) and energy-dispersive X-ray (EDS). The applied load, sliding velocity, SiC, Al 2 O 3 , and TiO 2 significantly affect the friction coefficient and wear loss. Chemical properties were investigated through Fourier-transform infrared (FTIR) analysis, and the peak values were identified. The analysis can be used to predict the tribological properties of Al-6063 MMC in engineering applications.
Fretting fatigue has attracted substantial research interest in recent decades owing to its relevance in a wide range of applications. This paper reviews previous studies and describes ongoing research. Particularly, only a few studies on bending fretting fatigue have been conducted. This review paper emphasizes the effect of bending fretting fatigue of different materials under different operating parameters. In addition, the damage mechanisms with respect to nature of failure of materials are also discussed. This paper can be used as a reference for design and development of modern technologies and selection of appropriate material in industries.
In industrial applications where contact behavior of materials is characterized, fretting-associated fatigue plays a vital role as a failure agitator. While considering connection, it encounters friction. Biomaterials like polytetrafluoroethylene (PTFE) and ultra-high-molecular-weight polyethylene (UHMWPE) are renowned for their low coefficient of friction and are utilized in sophisticated functions like the hip joint cup and other biomedical implants. In addition to the axial stresses, some degree of dynamic bending stress is also developed occasionally in those fretting contacts. This research investigated the fracture behavior of a polymer PTFE under bending fretting fatigue. Finite element analysis justified the experimental results. A mathematical model is proposed by developing an empirical equation for fracture characterization in polymers like PTFE. It was found that the bending stiffness exists below the loading point ratio (LPR) 3.0, near the collar section of the specimen. Along with fretting, the bending load forces the specimen to crack in a brittle-ductile mode near the sharp-edged collar where the maximum strain rate, as well as stress, builds up. For a loading point ratio of above 3, a fracture takes place near the fretting pads in a tensile-brittle mode. Strain proportionality factor, k was found as a life optimization parameter under conditional loading. The microscopic analysis revealed that the fracture striation initiates perpendicularly to the fretting load. The fretting fatigue damage characteristic of PTFE may have a new era for the biomedical application of polymer-based composite materials.
Cantilever beams, made of shape memory alloy (SMA), undergo much larger deflection in
comparison to those made of other materials. Again, cantilever beams with reducing
cross section along the span show much larger deflections compared to those
of constant cross section beams. Analysis was conducted for such a cantilever
beam with reducing cross-sectional area made of SMA, taking into account its
highly nonlinear stress–strain curves. A computer code in C has been developed
using the Runge–Kutta technique for the purpose of simulation. For rigorous
analysis, the true stress–strain curves in tension as well as in compression have been
used for the study. Moment–curvature and reduced modulus–curvature relations
are obtained from the nonlinear stress–strain relations for different sections of
the beam and used in the simulation. It is seen that load–deflection curves are
initially linear but nonlinear and convex upward at a high load. Furthermore,
the compressive stress in the beam is significantly higher than the tensile stress
because of asymmetry. Interestingly, for the different cases considered, it is found
that part of the SMA beam material may remain in the parent austenite phase,
mixed phase or in the stress-induced martensitic phase. Importantly, it is found
that more material can be removed from an SMA beam of uniform strength,
originally designed without considering geometric nonlinearity and the effect of
end-shortening. Comparison of the numerical results with the available theory shows
very good agreement, verifying the soundness of the entire numerical simulation
scheme.
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