Elastic Strain Values Research Articles

Clinical challenges of biomechanical performance of narrow-diameter implants in maxillary posterior teeth in aging patients: A finite element analysis.

This study evaluated the biomechanical performance of narrow-diameter implant (NDI) treatment in atrophic maxillary posterior teeth in aging patients by finite element analysis. The upper left posterior bone segment with first and second premolar teeth missing obtained from a patient's cone beam computed tomography data was simulated with cortical bone thicknesses of 0.5 and 1.0 mm. Three model groups were analyzed. The Regimen group had NDIs of 3.3 × 10 mm in length with non-splinted crowns. Experimental-1 group had NDIs of 3.0 × 10 mm in length with non-splinted crowns and Experimental-2 group had NDIs of 3.0 × 10 mm in length with splinted crowns. The applied load was 56.9 N in three directions: axial (along the implant axis), oblique at 30° (30° to the bucco-palatal plane compared to the vertical axis of the tooth), and lateral load at 90° (90° in the bucco-palatal plane compared to the vertical axis of the tooth). The results of the von Mises stress on the implant fixture, the elastic strain, and principal value of stress on the crestal marginal bone were analyzed. The axial load direction was comparable in the von Mises stress values in all groups, which indicated it was not necessary to use splinted crowns. The elastic strain values in the axial and oblique directions were within the limits of Frost's mechanostat theory. The principal value of stress in all groups were under the threshold of the compressive stress and tensile strength of cortical bone. In the oblique and lateral directions, the splinted crown showed better results for both the von Mises stress, elastic strain, and principal value of stress than the non-splinted crown. In conclusion, category 2 NDIs can be used in the upper premolar region of aging patients in the case of insufficient bone for category 3 NDI restorations.

Representative volume elements of strain/stress fields measured by diffraction techniques.

Finite-element modelling has been used to simulate local strains and stresses within free-standing polycrystalline slabs of W, Cu and W-Cu, heated with free or constrained boundaries. The elastic strain values in crystallites that satisfied the diffraction condition were used to simulate the lattice strain data that would be obtained from diffraction analysis, from which the average stresses within diffracting domains were computed. Comparison of direct-space stresses in the model with the average stresses determined from diffraction analysis shows that the representative volume elements (RVEs) required to obtain equivalent stress/strain values depend on the deformation mode suffered by the material. Further, the direct-space and diffraction stress values agree only under strict sampling and strain/stress uniformity conditions. Consequently, in samples where measurements are conducted in volumes smaller than the RVE, or where the uniformity conditions are not satisfied, further experimental and numerical techniques might be needed for the accurate determination of applied or residual stress distributions.

Improving concrete fatigue resistance with COVID-19 rubber gloves: An innovative sustainable approach

Since the COVID-19 outbreak in late 2019, a surprisingly large amount of personal protective equipment, such as medical rubber gloves, have been frequently used, and this medical waste can cause very major environmental problems. A multidisciplinary collaborative approach is needed to combat the pandemic and lessen the environmental risks associated with the disposal of medical waste. This study developed an innovative approach by incorporating shredded rubber glove fibers (RGF) into aggregates to enhance the fatigue resistance of concrete. In this study, different volume contents (0.5%, 1.0%, 1.5%, 2.0%) of RGF were added to the aggregate for the first time. The effects of different RGF contents on the fatigue characteristics of concrete were examined through repeated loading tests and SEM analysis. The results show that the width and number of cracks produced by rubber glove fiber concrete (RGFC) after repeated loading are significantly reduced compared with normal concrete (NC). Following repeated loading, RGFC exhibited higher total, plastic, and elastic strain values than NC, demonstrating greater deformability and elasticity. However, the maximum total strain growth rate and the total strain growth range of the RGFC group were only 2.26 × 10−3/time and 14.0%, which were significantly smaller than the 3.8 × 10−3/time and 31.7% of the NC group, showing better stability, corresponding to enhance the fatigue resistance of concrete. The interfacial transition zone (ITZ) was abnormally smooth with a thin thickness and no visible gaps were discovered, based on the results of SEM test performed on the RGFC. The findings obtained in this study may provide new ideas for the resource utilization of medical waste.

Investigation of the mechanical performance of the composite prosthetic keel based on the static load: a computational analysis

In this paper, the numerical simulation of the mechanical performance of a composite prosthetic keel structure under static load has been explored, and the findings of this inquiry have been included. The prosthetic keel is constructed from an epoxy and glass fiber composite, 3 percent weight (MWCNTs with SiC), and a carbon nanotube, which are utilized in conjunction with other materials to create the structure. The force that is applied in this example is 1,000 N, and it is applied in accordance with the boundary condition that has been previously established in this case. The ANSYS modeling software package was used to create the prosthetic keel model, which was meshed and created. Because of the total deformation, the fundamental simulation results of the prosthetic keel model have been converged in line with the total deformation, which was used as a reference to determine the total deformation. The major outcome of the current numerical analysis has been successfully validated by considering the findings of the earlier experimental study. The mechanical performance of the composite prosthetic keel structure is determined by four primary criteria, the results of which are based on the findings. Aspects to analyze include equivalent elastic strain, three-axis directed deformation, total deformation, and equivalent stress (von Mises). Although only 0.00058 mm total deformation is created by the imposed static load of 1,000 N (the least attainable value), it represents the largest total deformation. The equivalent stress (von Mises) responded to the load with a response of 0.045 MPa, which is quite small. Furthermore, the equivalent elastic strain has also been undertaken and it resulted in a value of elastic strain of 3.4*10^7.

The deformation characteristics of buried HDPE transfer lines in trenches under the effect of temperature

Today, the use of high-density polyethylene (HDPE) transfer lines is increasing day by day for drinking water, wastewater, sewerage networks, rainwater drainage lines, water transport structures, and natural energy sources, etc. In this study, flexible HDPE pipes were embedded in a trench to expose them to variable relative density and different thermal conditions so that the resulting deformation behavior could be investigated. Displacements and elastic strain values in the crown and spring line regions were measured. The main aim of this research was to determine the behavior of HDPE pipes under temperature effects within the framework of geotechnical principles to reflect real field conditions. As a result, pipes subject to vertical loading were tested under different relative density and thermal conditions. In the experiments carried out in a silica sandy trench, the deformations increased due to an increase in relative density. The maximum displacements and bending moment values were obtained at 50°C, which was the maximum thermal condition applied. An increase in temperature increased the deformation values due to the resulting decrease in the modulus of elasticity.

3D Model of Bone Scaffolds Based on the Mechanical Behaviour for a Hybrid Nano Bio-composites

Ceramic/polymer Nano composites in the view of possessing design uniqueness and property combinations have gained a great attention and reported to be the materials of the 21st century that are not found in conventional composites. In the present work, an attempt has been made to study, develop and improve the bio-mechanic for a designed and fabricated Ceramic/polymer bio-composite for a human natural bone repair and replacement in the case of complex fracture and bone diseases by adding the Nano fillers ceramic particles to the Polymer Matrix Nano composites (PMNC) for fabricated a hybrid Titanium dioxide and yttria stabilized zirconia reinforced high density polyethylene (HDPE) matrix bio-composites properties. These bioactive composites have been investigated by using hot pressing technique at different compression pressures of (30, 60, and 90 MPa) at a compounding temperature of (180, 190, and 200 °C). The SOLIDWORKS 17.0 and the finite element ANSYS 15.7 software programs were used to the simulation, modelling and analysing of femur bone biomechanics that can withstand the highest stresses and strains. The response surface methodology (RSM) technique was used to improve and verify the results. For all the fabricated Nano bio-composites systems, the results showed that the obtained output parameters values were increased with increasing the process input parameters, also the vice versa for the strain energy and equivalent elastic strain values, also the Nano ceramic compositions represented the main factor influenced the results. The main investigates results of the current research deduced that for the increase of the Nano ceramic powder (TiO2) contain from 1% to 10%, the compression fracture strength and the micro-Vickers hardness values increased by 50% and by 8.45%, respectively, and when adding 2% of zirconia (ZrO2), an additional increase in the compression fracture strength and micro hardness by 28.21% and 40.19% achieved, respectively. When using 10% TiO2 + 2% ZrO2/HDPE bio-composite at highest compact temperature of 200 °C and compounding pressure of 90 MPa, the strain energy and the equivalent elastic strain reduced by 82.69% and 14.53% when compared with using of 1% TiO2 content. While when increasing the nano ceramic content from 1% to 10% without adding the ZrO2 nano filler, they reduced by 142.25% and 67.81%, respectively. The maximum equivalent von Misses stress obtained is equal to 39.957MPa and when increasing the nano ceramic content from 1% to 10%, the stress safety factors and fatigue live values increased by 58.38% and by 46.28%, respectively and when adding 2% of zirconia (ZrO2), the stress safety factor reached its maximum values, with an additional increase in its values by 21.42% and 69.40%, respectively. These results give great choices to use successful in vivo tests and for a better life performance with any age, patient status and degree of injury.

Creep behavior of polymeric adhesive joints exposed to different environmental conditions

AbstractThis article intends to examine the creep response of single‐lap adhesive joints (SLAJs) exposed to different environmental and temperature conditions. Therefore, SLAJs were fabricated and then immersed in seawater and deionized water at 40°C for 24 hours before conducting creep tests. The experimental results showed that seawater had lower detrimental effect on the creep and elastic responses of SLAJs than deionized water. The shear creep and elastic strain values of SLAJs immersed in deionized water increased averagely by 19.8% and 43%, respectively, whereas those strains for SLAJs immersed in seawater increased averagely by 2.1% and 28.8%, respectively, compared to SLAJs maintained in dry condition. This was because of the higher moisture ingress of adhesives aged in deionized water than in seawater due to the osmosis phenomenon. Moreover, the results showed 23% and 14% increase in shear creep and elastic strains, respectively, by increasing the water temperature from 30°C to 50°C. Furthermore, the time‐dependent responses of SLAJs immersed in different environments with different ageing temperatures were simulated by Burgers rheological model.

Relaxation of Residual Stresses in Bearing Rings Based on the Optimal Geometric Setup of Equipment for Centerless Running

This paper discusses the technological method of residual stress relaxation of bearing rings by centerless running with cylindrical rolls. Described a new approach to relieve residual stresses by centerless running of elastically-deforming rolls on the basis of the geometrical setup of the equipment. It was found that geometrical setup of the equipment influences an elastic strain of parts and the degree of residual stress relaxation. We obtained a mathematical model for calculation of setup parameters to ensure the required variation value of elastic strain of the part. The results of experiments confirm the influence of the geometric setup on the magnitude of residual stress relaxation.

Hot radial shear rolling and rotary forging of metastable beta Ti-18Zr-14Nb (at. %) alloy for bone implants: Microstructure, texture and functional properties

In this study, a novel combination of hot radial shear rolling and rotary forging operations was applied to Ti-18Zr-14Nb shape memory alloy with the objective of forming a long-length bar stock for bone implants fabrication. Evolutions of the microstructure, texture, mechanical properties, and functional fatigue behavior of the fabricated bar stock were monitored along the technological workflow. Radial shear rolling leads to the formation of a strongly heterogeneous microstructure along the cross-section of the deformed bar stock. In the external zone of the bar stock, in the extraction direction, a dynamically recrystallized structure (d ≈ 25 μm) with the <111> fiber texture is formed. As we approach the central area, the grain size increases to d ≈ 130 μm and the texture becomes random. After the subsequent rotary forging, the alloy exhibits a dynamically polygonized substructure of β-phase with a more homogeneous across-the-section grain size distribution (d ≈ 34–43 μm) and a weak <212> texture. In this structural state, the alloy offers the following set of properties, which make it suitable for implant applications: low Young's modulus (E = 41 GPa), high value of elastic strain (e = 1.11%), and superior functional fatigue behavior with a low level of accumulated strain. In the forged condition, a calculated limit for the recovery strain for a weak <212> texture is about 5%.

LOADING ANALYSIS ON ALLOY WHEELS TYPE-253 SIZE 6.5 X 15JJ BASED ON SNI 1896:2008 WITH FINITE ELEMENT METHOD

This study analyzes the loading on the model wheel-253 size 6.5 x 15JJ based on SNI 1896: 2008 with finite element method. This load analysis tested the resistance to dynamic radial fatigue on alloy wheels by using load simulation with quasi-static failure mode approach ie failure mode which is independent of time, and its resistance to failure is expressed with strength. Test wheels are said to fail if there is crack (crack) by giving the liquid penetrant. Crack conditions in the simulation can be seen from the stress and elastic strain. The equivalent elastic stress and elastic strain values that occur on the rim must be less than the Ultimate Tensile Stress (UTS) and the elastic strain at break. The properties values for Aluminum A356-T6 material for UTS of 228 N/mm 2 and strain elastic fracture values obtained from a plastic material strain of 0.059 m/m.

Extreme values of elastic strain and energy in sine-Gordon multi-kink collisions

In our recent study the maximal values of kinetic and potential energy densities that can be achieved in the collisions of $N$ slow kinks in the sine-Gordon model were calculated analytically (for $N=1,2$, and 3) and numerically (for $4\le N\le 7$). However, for many physical applications it is important to know not only the total potential energy density but also its two components (the on-site potential energy density and the elastic strain energy density) as well as the extreme values of the elastic strain, tensile (positive) and compressive (negative). In the present study we give (i) the two components of the potential energy density and (ii) the extreme values of elastic strain. Our results suggest that in multi-soliton collisions the main contribution to the potential energy density comes from the elastic strain, but not from the on-site potential. It is also found that tensile strain is usually larger than compressive strain in the core of multi-soliton collision.

Calculation of Technological Limits in Designing High-Speed Operations

The paper considers the technique of technological limit calculation for high-speed operations on CNC machines. The relationships between the parameters of the technological system and pre-set limits are calculated and presented graphically. An impact of radial tool feed on the workpiece surface undulation, required drive power, tool wear, workpiece surface temperature, and elastic strain values is demonstrated. The methods of calculating the technological limits are developed to ensure the accuracy and surface quality requirements with regard to technological capabilities of the equipment and tools. The technique is invariant and works either when all the limits exist or some of them. Consequently, the calculation of limits will be performed in dependence on the design environment for each specific machining conditions.

Microstructure and properties of metal/ceramic and ceramic/ceramic multilayer coatings on titanium alloy Ti6Al4V

The paper presents results concerning microstructure and mechanical properties of the metal/ceramic and ceramic/ceramic multilayer coatings obtained on Ti6Al4V alloy by the PVD (Physical Vapour Deposition) vacuum arc method. During the work Cr/CrN, Ti/TiN and CrN/TiN multilayer coatings were deposited with the similar total thickness but a different number of constituent layers. Focus ion beam sample preparation followed by STEM (Scanning Transmission Electron Microscopy) observations were performed in order to analyze the influence of phase composition and the number of layers on the microstructure of multilayer coating. The effect of these parameters on the hardness and Young modulus of the coatings obtained by nanoindentation technique was also investigated. These results were then used to calculate the values of elastic strain to failure (H/E) and resistance against plastic deformation (H3/E2).The results revealed that the obtained multilayer coatings differed in microstructure due to the different type of interfaces. Coherent, semi-coherent interfaces or interfaces with a transition layer influence the growth mechanism of the coatings and affect grain size. The investigation revealed that the grain size of the coatings also depends on the bi-layer period (number of layers). However, this effect was opposite for the metal/ceramic and ceramic/ceramic coatings due to the type of interface. The results showed that increasing the number of layers improved the mechanical properties of the Cr/CrN multilayer coatings. However, this relationship was not observed for CrN/TiN.

Elasticity Reinforcement in Propylene–Ethylene Random Copolymer Stretched at Elevated Temperature in Large Deformation Regime

Tensile deformation behavior of a random propylene–ethylene copolymer with 12 mol % ethylene counits at room temperature and 63 °C was investigated using the in situ small and wide-angle X-ray scattering techniques. Under both conditions, the deformation mechanism changed from slip of crystalline lamellar blocks to stretching induced melting and recrystallization process at a critical strain of about 0.9. This critical strain in tensile deformation of semicrystalline polymers normally marks the starting of plateau value of elastic strain. Further stretching leads to increase of plastic deformation only due to the fibrillation. However, a peculiar elasticity reinforcement was observed at strain larger than 1.3 when the sample was stretched at 63 °C. Wide angle X-ray scattering results indicate that at this strain of 1.3 fibrillation of the originally unoriented crystals finished so that further stretching leads to a deformation of a rather stable entangled network embedded by fibrils that possesses high elasticity.

Effects of interlayer thickness and the substrate material on the adhesion properties of CrZrN coatings

To confirm the influence of the interlayer thickness and substrate material on adhesion properties, CrZrN coatings with various Cr interlayer thickness were deposited on AISI H13, high speed steel, and tungsten carbide using unbalanced magnetron sputtering. The adhesion strength showed maximum value at 300 nm of the interlayer, but as the interlayer increased further to 450 nm, the adhesion strength decreased. The adhesion properties of the coatings were dependent upon not only interlayer thickness but also the substrate materials. The adhesion strength of the coating were measured 12, 32, 53 N on the tungsten carbide, AISI H13 steel, high speed steel, respectively and three different failure modes such as buckling spallation, wedging spallation, and chipping were observed on each substrate. The difference in adhesion properties could be attributed to the difference in value of elastic strain to failure (H/E) among the CrZrN coating, the interlayer, and the substrates material.

Finite element analysis of stress and strain distributions in mortise and loose tenon furniture joints

We studied the effect of loose tenon dimensions on stress and strain distributions in T-shaped mortise and loose tenon (M&LT) furniture joints under uniaxial bending loads, and determined the effects of loose tenon length (30, 45, 60, and 90 mm) and loose tenon thickness (6 and 8 mm) on bending moment capacity of M&LT joints constructed with polyvinyl acetate (PVAc) adhesive. Stress and strain distributions in joint elements were then estimated for each joint using ANSYS finite element (FE) software. The bending moment capacity of joints increased significantly with thickness and length of the tenon. Based on the FE analysis results, under uniaxial bending, the highest shear stress values were obtained in the middle parts of the tenon, while the highest shear elastic strain values were estimated in glue lines between the tenon surfaces and walls of the mortise. Shear stress and shear elastic strain values in joint elements generally increased with tenon dimensions and corresponding bending moment capacities. There was consistency between predicted maximum shear stress values and failure modes of the joints.

Nonuniform Elastic Deformation of Nanofilms Formed from Nial and Feal Alloys

Using MD techniques, uniaxial tension of nanofilms made from NiAl and FeAl alloys is investigated at different temperatures. It is found out that the films undergo elastic deformation to fracture at the strains within 35–40 %. The stress-strain curves from these films constructed for the strain-controlled tensile loading contain a region where the increase in strain is accompanied by a decrease in tensile stress, which suggests a negative rigidity of the films. The deformation of these nanofilms in the region of low thermodynamic stability and instability is attributed to the formation of domains with different elastic strain values. As the temperature is increased, both the deformation to fracture and the negative rigidity decrease. For FeAl, nonuniform elastic deformation and negative rigidity are observed in a wider temperature range (up to 1000 K) than for NiAl (up to 300 K), which is 0.65 and 0.16 of their melting temperatures, respectively. An introduction of prismatic dislocation loops into the structure of nanofilms gives rise to their hardening due to generation of internal stresses resulting in compression of the surface layers.

Emission and strain in InGaAs/GaAs quantum wells with InAs quantum dots obtained at different temperatures

The photoluminescence (PL), its temperature dependence and X ray diffraction (XRD) have been studied in the symmetric In0.15Ga0.85As/GaAs quantum wells (QWs) with embedded InAs quantum dots (QDs), obtained with the variation of QD growth temperatures (470–535°C). The increase of QD growth temperatures is accompanied by the enlargement of QD lateral sizes (from 12 up to 28nm) and by the shift non monotonously of PL peak positions. The fitting procedure has been applied for the analysis of the temperature dependence of PL peaks. The obtained fitting parameters testify that in studied QD structures the process of In/Ga interdiffusion between QDs and capping/buffer layers takes place partially. However this process cannot explain the difference in PL peak positions.The XRD study has revealed the high intensity peaks which correspond to the diffraction of X ray line from the (200) crystal planes of cubic GaAs. It was shown that the XRD peak is the superposition of the diffraction from the GaAs substrate and GaAs layers of quantum wells. The position of diffraction peaks related to the cubic GaAs substrate coincides with the very well-known XRD data for the bulk GaAs. At the same time the (200) diffraction peaks in GaAs epitaxial layers shift to the high angles in comparison with the bulk GaAs, testifying the compression strain in GaAs epitaxial layers. The value of elastic strain has been estimated. The minimum of elastic strain is detected in the structure with QD grown at 510°C that manifests itself by the higher QD PL intensity and lower PL peak energy.

The influence of hydrogenation on the redistribution of indium in a Pd-In-Ru alloy in the course of relaxation

Variations of the lattice constant and the value of elastic strain in 50 μm foil of Pd-5.3 at %-In-0.5 at %-Ru alloy in the course of its prolonged relaxation under normal conditions after electrolytic hydrogenation were analyzed using the X-ray diffraction technique. Nonmonotonic variations of the concentration of indium atoms were revealed in the subsurface layer of the foil.

장지간 가설교량에서 프리스트레스의 도입방법과 텐던배치에 따른 내하력의 영향

최근 교량설계에서 외부 프리스트레스를 도입한 장지간 및 효율적인 단면활용 등과 같은 연구가 활발하게 진행되고 있다. 강구조물에 프리스트레스를 도입하면 큰 하중에서 탄성변형의 극한값이 증가하게 되어, 강재량을 줄일 수 있고, 비용의 측면에서 경제성이 있는 것으로 평가 되었다. 이러한 이유 때문에 우리나라에서도 최근 가설교량 시공시 프리스트레스를 도입하여 응력보정 및 처짐보정이 가능하고, 비교적 작은 단면으로 장지간 교량을 시공할 수 있어 통수단면을 충분히 할 수 있는 여러 가지 공법이 개발되고 있다. 따라서 본 논문에서는 가설 강교량에 프리스트레스 도입방법 및 고강도 텐던의 배치에 따른 영향, 강판과 고강도 텐던의 복합구조에 대한 효과를 기존 가설공법과 비교하여 검증 하고자 한다. In recent bridge design, studies on application of external prestress have actively been conducted. When prestress is applied to steel structures, the limit value of elastic strain with large load increases with reduction of steels, this method is economic in cost. According to study by Brodka (1969), steel plate bridges with prestress has an effect on cost saving of about 15% compared with structures without prestress. For that reason, our country recently adopted this method in construction of temporary bridges and various engineering technologies have been developed which made stress correction, droop correction and long-span construction possible with relatively small cross sections. This study verifies the method of application of prestress in temporary steel structures, the influence of high-strength tendon arrangement and the effects of composite structures of steel plates and high-strength tendons based on existing method.