جستجوی مقالات مرتبط با کلیدواژه "elastic modulus" در نشریات گروه "مواد و متالورژی"

In this study, mechanical properties, including elastic modulus and impact strength of nanocomposites based on polypropylene and polyethylene, linear low-density blends, in the presence of titanium oxide nanoparticles have been studied. 0, 2 and 4 wt% titanium dioxide nanoparticles were added to the basic ingredients polypropylene / polyethylene linear low density with a fixed ratio of 60/40 wt. % to reach the final composition that was prepared using an extruder. Tensile and impact tests were carried out in order to determine the elastic modulus and impact strength of compounds. It was observed that the presence of titanium dioxide nanoparticles at 2 wt. %, elastic modulus and impact strength compared to the basic polypropylene/polyethylene linear low-density increase and the presence of higher level of titanium dioxide nanoparticles up to 4 wt. % decrease mechanical properties of compounds. It was also seen that usilng low weight percent of nano particles, increase impact strength of the samples up to 7 percenrt.

In the present study, an investigation of coefficient of thermal expansion, elastic modulus, yield strength of compression, wear resistance and hardness of 3 layers called inner, intermediate and outer are investigated for functionally graded Al based cylindrical shell containing 26 wt.% Cu and 8 wt.% Si. The microstructure is studied by using TESCAN MIRA3 field emission scanning electron microscopy (FESEM) and TITAN scanning transmission electron microscope (STEM) is revealed that intermetallic compound content reaches its maximum volume fraction at the inner layer with 33.3 Vol.% and then reduces gradually to 26.4 Vol.% at outer layer. In addition, wear rate was 5.4gr/m2 and hardness was 153 HV at inner layer and then gradual increase by 7.07 gr/m2 and decrease by 149 HV, respectively at outer layer. Moreover, the value of yield strength of compression is determined 275, 460 and 415 MPa at outer, intermediate and inner layers, respectively.

In this research, numerical and experimental investigations of the elastic properties of epoxy reinforced with carbon nanotubes (CNTs) are presented. First, finite element modeling of elastic modulus is simulated without considering interfacial debonding between the matrix and CNT.It was observed that the results of the model differ greatly with experimental results whichthe reason is that it assumes full connectivity matrix and the CNTs. In the next step with regard to the separation, the simulation was conducted. By calculation of critical stress and defining the cohesive surface elements in Abaqus, elastic modulus was calculated.Finally,by assuming curvature for CNTs, the simulation results are presented. The comparative results of this study indicate that the presented numerical method exibits a good agreement with experimental data when interfacial debonding is considered.

Titanium and its alloys are known as one of the most significant metallic materials used in the orthopedic and dental implants due to their excellent mechanical properties, corrosion resistance and biocompatibility. One of the main issues in dental implant is the fabrication of the biomaterials that have early and sufficiently strong bonding with the surrounding bone. In the present study, porous Ti6Al4V scaffolds were produced using magnesium as a space holder by powder metallurgy. The specimens were sintered in 950°C, below the β transition temperature, close to magnesium vaporization point. To evaluate the porosity and effect of magnesium on it, the micro structure was investigated by optical microscopy and SEM and then mechanical properties and electrochemical corrosion behavior of the specimens were studied. Biocompatibility was investigated by MTT test, and it was deduced that the cell proliferation and biocompatibility was increased with increasing the porosity. This investigation showed that the compressive strength and elastic modulus of the porous scaffold with 10% magnesium and 31% porosity are 155MPa and 9GPa, respectively and close to dental bone. Also, the corrosion results and cell proliferation showed the appropriate corrosion behavior and osseointegration of this scaffold. Due to the importance of strength in the dental implant and according to these results, the Ti6Al4V scaffold with 10%Mg could be an advanced alternative for clinical applications which two factors of strength and osseointegration are required.

In this research, stiffness of polymer-clay nanocomposites was simulated by Mori-Tanaka and two and three dimensional finite element models. Nanoclays were dispersed into polymer matrix in two ways, namely parallel and random orientations toward loading direction. Effects of microstructural parameters including volume fraction of nanoclays, elastic modulus of nanoclays and interphase, thickness of interphase, aspect ratio of nanoclays and random orientation of nanoclays on elastic modulus of the nanocomposite were investigated by finite element model. Comparing the simulation with experimental results showed that the Mori-Tanak simulation results were closer to the experimental results. Analysis of results showed that the volume fraction of nanoclay, elastic modulus of nanoclay, deviation of nanoclay layers with respect to loading direction, nanoclays aspect ratio, thickness of interphase and the elastic modulus of interphase had respectively the most to the least effect on elastic modulus of nanocomposite.