Nonlinear oscillations of particle-reinforced electro-magneto-viscoelastomer actuators

This work presents the dynamic modeling and analysis of a particle-reinforced and pre-stressed electro-magneto-viscoelastic plate actuator. The actuator belongs to a smart actuator category and is made of an electro-magneto-active polymer filled with a particular volume fraction of suitable fillers. An energy-based electro-magneto-viscoelastic model is developed to predict the actuator response and interrogate the impact of particle reinforcement on the dynamic oscillations of a pre-stressed condition of the actuator. An Euler–Lagrange equation of motion is implemented to deduce the governing dynamic equation of the actuator. The findings of the model solutions provide preliminary insights on the alteration of the nonlinear behavior of the actuator excited by DC and AC dynamic modes of actuation. It is observed that the enrichment in the particle reinforcement characterized by the amount of fillers strengthens the polymer and depleted the associated level of deformation. Also, the depletion in the intensity of oscillation and enhancement in the frequency of excitation is perceived with an increase in the particle reinforcement. In addition, the time-history response, Poincare plots and phase diagrams are also plotted to assess the stability, periodicity, beating phenomenon, and resonant behavior of the actuator. In general, the current study provides initial steps toward the modern actuator designs for various futuristic applications in the engineering and medical field.

Properties of aluminum metal matrix composites manufactured by selective laser melting

The most promising metal processing additive manufacturing technique in industry is selective laser melting, but only a few alloys are commercially available, limiting the potential of this technique. In particular high strength aluminum alloys, which are of great importance in the automotive industry, are missing. An aluminum 2024 alloy, reinforced by Ti-6Al-4V and B4C particles, could be used as a high strength alternative for aluminum alloys. Heat treating can be used to improve the mechanical properties of the metal matrix composite. Dynamic scanning calorimetry shows the formation of Al2Cu precipitates in the matrix instead of the expected Al2CuMg phases due to the loss of magnesium during printing, and precipitation processes are accelerated due to particle reinforcement and additive manufacturing. Strong reactions between aluminum and Ti-6Al-4V are observed in the microstructure, while B4C shows no reaction with the matrix or the titanium. The material shows high hardness, high stiffness, and low ductility through precipitation and particle reinforcement.

An Overview of Wear and How to Improve Wear Resistance

Wear is discussed in this study, as well as its impact on component performance and lifespan. It was mentioned how researchers are working to enhance the performance of materials. Due to enhanced hardness and finer grain structure, increased wear resistance has been recorded. Due to the particle strengthening process, it has also been observed that particle reinforcement improves wear resistance.

Investigation of mechanical and tribological behaviour of expanded perlite particle reinforced polyphenylene sulphide

In this study, polyphenylene sulphide was used as a matrix material due to its superior engineering properties. Expanded perlite is formed substantially from silica oxides, and it is a volcanic based and porous structure material. Its low price and low density make it very usable as a filler material. For this reason, expanded perlite reinforced polyphenylene sulphide matrix composites were prepared at various weight ratios (0, 1, 3, 5, and 10 wt%). Mechanical and tribological characterizations were done with tensile tests, hardness measurements, solid particle erosion, ball on disc, and scratch tests. According to the tensile test results, a synergistic effect was observed in mechanical properties by using perlite as a reinforcing agent. As expected, perlite reinforcement resulted in an increase in the modulus of 54% in composites. As well as tensile strength of the composite increased by approximately 13%. Furthermore, the perlite particle reinforcement improved the adhesion resistance by 73% and the scratch resistance by 30%. On the other hand, especially at low impact angles, perlite particle reinforcement decreased the erosive wear resistance of the pure polyphenylene sulphide polymer by 50%. Furthermore, expanded perlite reinforcement decreased the plastic deformation ability of polyphenylene sulphide. In consequence of this study, it has been found that expanded perlite particles can be used as an alternative filler instead of conventional reinforcing particles.

High modulus polyimide particle-reinforcement of epoxy composites

A novel class of fully organic composite materials with well-balanced mechanical properties and improved thermal stability was developed by incorporating highly crystalline, hydrothermally synthesized polyimide microparticles into an epoxy matrix.