Papers by Keyword: Strain

Abstract: In this study, we delve into the electromechanical characteristics of the CF monolayer using ab initio theory. The CF monolayer possesses flexible mechanical properties with relatively small elastic coefficients. Additionally, our findings reveal that the CF monolayer can sustain significant strains of up to 24% along the x-axis and 14% along the y-axis under tensile stress. The critical stresses corresponding to these strain values are 21.79 N/m and 17.46 N/m, respectively. Specifically, as the charge varies from 0.00 to -0.07 e/atom, there is an increase in the failure strain along the x-axis, from 24% at equilibrium to 30% at -0.07 e/atom. At equilibrium, the CF monolayer is identified as a direct semiconductor with a band gap of 3.21 eV. Despite charge doping, the monolayer CF retains its direct semiconductor properties. Notably, the energy band gap of the CF monolayer is dependent on charge doping and can be modified by about 10%. Furthermore, the electronic properties of the CF monolayer suggest its potential applications in spin-polarized electronics. Our results provide evidence of the applicability of the CF monolayer in electronic devices.

Abstract: Piezoelectric ceramics possess very high piezoelectric coefficients but lacks the conformability for using them in flexible devices, in high-resolution sensing devices that can be integrated to human skin and other such applications. This problem can be resolved by blending them in appropriate proportion with polymers which are intrinsically light weight, stable and flexible. In this paper polymer composites xPZT– (1-x) PVDF (x= 0, 0.025, 0.05, 0.10, 0.15, 0.20 and 0.25) were prepared by solution casting method and their dielectric and its mechanical properties were studied. Given that PZT has a very high dielectric value, the composite's dielectric constant grew as the filler concentration increased which shows better dipole alignment in the composite. With an increase in filler concentration, the composite loses flexibility and tensile strength. Due to their greater Young's modulus than pure PVDF film, the films with compositions x=0.025 and x=0.05 could have better piezoelectric characteristics.

Abstract: X-Ray diffraction measurements of lattice parameter were performed for (111) and (100) oriented 3C-SiC/Si epiwafers. Strain of 3C-SiC epilayer and Si substrate were estimated and the result was compared with routine wafer deformation measurements. An unexpected discrepancy was observed between XRD and curvature measurements for (100) oriented samples.

Abstract: A method for mitigating loss of conformational stability in 150 mm n-type 4H SiC wafers was investigated. Modifications to the physical vapor transport (PVT) process used to grow the parent bulk crystals, combined with post-growth thermal treatment, were examined as means of reducing the internal stresses hypothesized to promote instability. The magnitude of the stresses was analyzed by mechanically thinning sets of wafers produced from each process to determine the critical thickness of stability loss. The average critical thickness was found to be reduced by 13% via growth cell modification, at a reduced level of thermal treatment relative to a control process, with all wafers becoming unstable greater than 30 μm below the minimum recorded production thickness. Assessment of the spatial uniformity of dislocations indicated that lower conformational stability corresponded to elevated densities of basal plane dislocations (BPDs) and threading edge dislocations (TEDs) at the wafer edge relative to the center.

Abstract: In this paper, tests were performed by monitoring changes of strain amounts and their distribution by digital image correlation during static tensile testing of steel. The influence of different combination of speckles application on the sample surface (white speckles on the black sample surface and black speckles on the white sample surface) during cold deformation of steel was tested with the non-contacting digital image correlation. Strain amounts obtained by digital image correlation analysis of tested samples, with white on black and black on white painted speckle patterns, were compared. Different analysis for determining and monitoring strain amounts, provided by digital image correlation software, were used in this paper. The strain amounts were compared during cold deformation until the occurrence of sample fracture in both combinations of speckles application on the sample surface. Research has shown the importance of proper sample preparation for determination strain amounts and insignificant minor differences of strain amounts, between different sample preparations for digital image correlation, during cold deformation of tested steel.

Abstract: The trawler winch is a main winching tool in the fishing operation of trawler. The disturbing influence of various factors such as sea wind and waves, change in the size of the catch and the turning of the fishing vessel during the operation of the trawler will cause unbalanced force on the wire rope of the two winches, which will easily cause the deformation and damage of the fishing net facilities and directly affect the improvement of the fishing yield and increase the harvest. In order to compensate for the change of the tension of the winch tractor during the operation of the trawler, the change of the load tension caused by the wave, or the rotation direction of the fishing vessel, and to ensure the good shape of the net opening, an electro-hydraulic control technology was used to design an automatic trawler tension controller. The tension control method of the trawler is investigated. The tension sensor is used as the input information of the electrical signal of the trawler's left and right trawler, which is measured indirectly and transmitted to the controller for logical operation, and the output torque of the hydraulic motor is changed by controlling the pilot overflow, which drives the trawler winch to adjust the tension of the left and right trawler to achieve the dynamic balance of the control system. In order to solve the problem of the tension of the trawl and the influence of the length change on the trawl, we designed an intelligent control system combining PLC control system and hydraulic system and used AMEsim hydraulic simulation software system to model and simulate it, the results show that without PLC control the torque of hydraulic motor 1 is 2387.7NM, the torque of hydraulic motor 9 is 2148.64NM the difference is 239.06 NM uneven force on both sides of the trailing platform, after adding PLC adjustment torque is obviously controlled torque to maintain about 2300NM, within a certain range to play a reliable adjustment effect.

Abstract: The primary purpose of the structural study on the 4.2-meter-long Jaloe Kayoh boat is to analyze the FEA of E-glass and ramie fiber composites, as well as the polyester resin. The hand lay-up method was used in this study to manufacture specimens following the ASTM D638-02 standard, while the tensile test was performed under the ASTM D790-02 standard. Based on the simulation results, the data analysis method was used to visualize the relationship between the stress and strain strength parameters on the structure, as well as a reaction force and displacement, which were related to the centralized loading on the walls and hull of the Jaloe Kayoh boat with a minimum loading variation of 539.3 N and a maximum loading variation of 2157.4 N. The maximum loading of the stress strength on the hull wall of Jaloe Kayoh was obtained at a load of 220 kg or 2157.4 N. The stress values obtained were 4.212e+09 N/mm2 for E-glass fiber and 3.998e+09 N/mm2 for ramie fiber. The highest Reaction Force values obtained were 4.369e+03 N for E-glass and 4.952e+03 N for ramie fiber. The highest displacement value was obtained, which was 2.620e-02 m for E-glass fiber and 2.662e-02 m for ramie fiber. Based on the simulation results, E-glass and ramie fibers are still safe and feasible to use as a base or initial layer, or one of the supporting layers, for lamination on one of the materials for the Jaloe Kayoh boat's walls and hull.

Abstract: In this study, strain measurement can be analyzed in sub-10nm SiGe layer (~7 nm) grown on [100] Si substrate by chemical vapor deposition at the nanoscale level. The measurement technique is based on transmission electron microscopy (TEM), in which high-resolution transmission electron microscopy (HRTEM) image is combined with the image processing of geometric phase analysis (GPA) software. In this case, GPA analyzes the HRTEM images formed at the [011] zone axis to obtain information about strain maps along the [100] growth direction of the nanoscale SiGe region. The strain analyzed in the SiGe layer is within 1.6-2.9% with high precision and high spatial resolution.

Abstract: Since the C₂N-h2D crystal was efficiently synthesized, this study aims to investigate bandgap modulation of nanoribbons and nanotubes. Appling Density Functional Theory (DFT), the band-gap modulation of C₂N-h2D nanomaterials is researched under elastic strains. The results of the current study indicate that the band gap of C₂N-h2D nanoribbons and nanotubes can be tuned along two directions, namely, stretching or compressing nanoribbons and nanotubes when ɛ is changed from -10% to 10% in zigzag and armchair, respectively. This study also finds that the band gap of the C₂N-h2D nanoribbons and nanotubes change with increase of widths or the radii of nanotubes. Therefore, the great potential applications of the C₂N-h2D nanomaterials have been predicted in strain sensor and optical electronics at nanoscale.

Abstract: 3D simulation by the finite element method (FEM) using MSC.Marc of sclerometric test with a conical indenter of a nickel aluminide intermetallic coating has been determined. The effect of the coating thickness and composition on the strain distribution has been determined. It is shown that an increase in the thickness of the coating makes it possible to reduce the magnitude of the maximum plastic strain. NiAl and Ni₃Al coatings reduce maximum value of plastic strain and the penetration depth of indenter by 40% compared to a coating made of Ni₂Al₃.