A Comparison Criterion for the Flexure Shape in Constant-Torque Compliant Joints

Compared to conventional vehicles, the advantages of electric vehicles are more significant acceleration, no exhaust emissions, making electric vehicles more environmentally friendly, minimal maintenance because there are not many components used in electric cars. This research method is used to develop the chassis design of an electric trike, and then the chassis design is analysed using Solidworks software. The chassis with a thickness of 2.4 mm weights 29.6 kg with a maximum value of stress, displacement, strain, and other factors. Safety as follows: 7,582 x 107 N/m2, 2,567 mm, 3,368 10−4 and 3.5, 2 mm thick chassis weighs 25 kg with maximum stress, displacement, strain, and safety factor values as follows: 1.079x108 N/m2, 3.160 mm, 3.981 10−4 and 2.5 then the chassis thickness of 1.6 mm weights 20.3 kg with the maximum stress, displacement, strain, and safety factor values as follows: 1.809 x 108 N/m2, 4.190 mm, and 9.388 10−4. Chassis with a thickness of 2 mm using a rectangular tube and ASTM A53 material has a safety factor value that is by the requirements and the maximum stress value on the chassis does not exceed the allowable stress value and weight.

Lawn mower blade is an essential part of the unit as a machine. It is, therefore, necessary for its design to be formidable in order to prevent failure in service. This work presents analytical and finite element (FE) relationship of the structural integrity of a lawn mower blade. For the analytical (theoretical) approach, the blade was assumed as a rotating disc, while for the FEA a 3-D solid model of the mower blade was generated, discretized and loaded statically, at the cutting edge using Solid Works. A uniformly distributed load of 400 N/m was applied in both cases. From the results obtained, the maximum theoretical hoop stress value was about 47.4 MPa, while the maximum Von-Mises stress for FEA was about 49.42 MPa. That maximum hoop stress value was about 96% of the maximum Von-Mises stress value, which suggests a strong correlation and agreement between them, as they both occurred at the inner radius of the blade. The maximum theoretical hoop strain value was about 2.00 x 10 -4 mm/mm, while that of the maximum radial and FEA values were about 3.4 x 10-5 mm/mm and about 1.06 x 10-4 mm/mm, respectively. The maximum analytical displacement value was about 0.254 x 10-1 mm compared with FEA displacement value of about 2.50 x 10-1 mm. With the results obtained from both analytical and FEA approaches, the percentage analytical values relative to the maximum allowable values of stress, strain and displacement were about 17.9%, 77.8% and 2.3%, respectively, while the corresponding percentage of the FEA values to the maximum allowable stress, stain and displacement values were about 18.6%, 41.2% and 23.4%, respectively. The absolute percentage difference in stress between analytical value and FEA value was about 0.7%, while that for the strain and displacement values were approximately 36.6% and 21.1%, respectively. The difference in their respective corresponding values do not significantly affect the outcome of the results and their corresponding effect on the stress, strain and displacement. Overall, it was observed that the maximum stress, strain and displacement values obtained from both theoretical analysis and FEA were less than their corresponding allowable stress, strain and displacement values. With this result, the blade will not fail in service going by the induced stresses and assumptions adduced.

Based on nonlinear FEA software ANSYS, 3D simulation models of eighteen-type perforated plate that have different open-pore number was established. Analysis results indicate: Maximum equivalent stress of perforated plate mainly takes place on symmetry center of outer open-pore for open-pore area. With increasing open-pore number, maximum equivalent stress and each-direction maximum stress of perforated plate presents to enlarge trend. When open-pore number less than or equal to twelve, value of maximum equivalent stress mainly is decided by Z-direction maximum stress. When open-pore number greater than twelve, value of maximum equivalent stress mainly is decided by Y-direction maximum stress. When ratio m less than 2, with increasing ratio m, maximum equivalent stress and each-direction maximum stress of perforated plate presents to reduce trend. When X-direction and Y-direction open-pore numbe of perforated plate is basically equilibrium distribution, X -direction maximum stress is about equle to half of maximum equivalent stress.

Design of a new magnesium-based anterior cruciate ligament interference screw using finite element analysis

Seaweed is a plant that is adaptable and is used in a variety of industries, such as food, cosmetics, and medication. However, the current seaweed processing technique, which entails sun drying, is still highly traditional and requires a significant amount of time. To speed up draining and drying seaweed, we developed a hybrid energy-powered seaweed draining and drying. The tool capacity of this design is 50 kg, and it applies the Pahl and Beitz method. The selected design is variant 3 with the highest weight value of 7.74. The design outcomes produce the following tool specifications the drive is equipped with a diesel motor with a power of 3.5 Hp, 2.6 kW, and 3600 rpm, as well as three solar panels of the MCS1100 model, each with a capacity of 100 Wp. The container dimensions of 382 mm diameter and 500 mm height. The seaweed is to be dried at a rate of 29,3 kg/m2 per hour. The galvanized steel frame yielded a maximum working stress value of 126.223 N/mm2, which is lower than the material's yield strength value of 203.943 N/mm2. On the shaft made of S45C8 steel, the maximum working stress value after applying the load is 66.83 N/mm2, which is also less than the material's yield strength value of 350 N/mm2. This indicates that the stand and shaft design is safe, as the simulation process's maximum stress value does not surpass the material's yield strength value.

The mechanical properties of the main hydraulic cylinder, slider, and piston rod of hydraulic impact the overall performance in hydraulic press slow compression process. In this paper, a three beam four-column hydraulic press was regarded as the research object, the working principle of hydraulic press and the stress characteristics of important components of hydraulic press was analyzed, the mechanics model was set up, and thus established the optimization scheme of slider and piston rod; the finite element model of the important components of the hydraulic press was set up by using ANSYS software. The results show that the maximum pressure of the main hydraulic cylinder is 36.0032 MPa in the maximum liquid stress value 25 MPa;when the piston rod and the slider work at the maximum nominal force of 1000KN, the maximum stress occurs at the joint, and the value is 55.4125MPa. After optimization, the maximum stress value is 48.9255MPa, which effectively reduces the risk of stress. This result provides the basis for the design and application of the hydraulic press.

Drilling operations in deep tight reservoirs (>4000 m) pose significant challenges due to the complex nature of these formations. In this context, the application of mechanical specific energy has emerged as a valuable tool for understanding drilling challenges and optimizing operational parameters. However, a crucial aspect in MSE calculation is the accurate estimation of the rock strength properties. Conventionally, rock strength properties (e.g., unconfined compressive strength) are obtained from logs or laboratory tests performed on core plugs; however, UCS values may not accurately represent downhole or reservoir conditions. In this study, we address this limitation by proposing an unconventional method to estimate confined compressive strength, which is a key input parameter for MSE calculation. In this study, we developed an approach to leverage both triaxial test data and scratch test results for the target formation. Six core plugs were extracted from the formation, with each plug subjected to varying degrees of confining pressure. These pressure values ranged from zero to the maximum capacity of the triaxial test equipment. However, even at maximum capacity, the confining pressures applied during laboratory testing did not fully replicate the high confining pressures experienced in real downhole conditions. We calibrated the strength values obtained from triaxial tests using scratch tests performed on the surface core. The scratch tests provided continuous profiles of the rock strength across various confining pressures. Through regression analysis, we established a relationship between rock strength and confining pressure. This allowed us to derive a trend line, enabling the prediction of rock strength at different downhole stresses experienced in the field. By incorporating true downhole confining pressures, this approach facilitated the accurate estimation of confined compressive strength. Our regression analysis revealed a strong linear relationship between confining pressure and rock strength. Using this relationship, we projected the maximum horizontal stress value as the maximum stress in the study area attributed to the strike-slip regime. Taking this maximum stress value as our maximum confining pressure, we found that the confined compressive strength values were significantly higher (approximately 4-6 times) than the conventional unconfined compressive strength values obtained from laboratory tests. However, when comparing our MSE values with conventional UCS values, we found that the UCS values were higher than the MSE values. This discrepancy contradicts the principles of MSE theory. The significant discrepancy between UCS and MSE values prompted us to use CCS values in MSE calculations, which resulted in a more logical outcome with a high degree of confidence. The integration of triaxial and scratch test data for estimating confined compressive strength represents a significant advancement in MSE calculation for tight sand rocks. This approach significantly improves the accuracy of MSE analysis, providing valuable insights for drilling optimization and operational efficiency.

The present study seeks to increase the life term of fully cemented total hip replacements by minimizing the stress values within the cement mantle. Three-dimensional (3D) finite element analyses have been carried out to investigate the effects of varying cement thickness on the von-Mises stress of a cement mantle. The magnitude and location of maximum von-Mises stress within the cement mantle have been studied for both straight and tapered prosthetic stems. For prosthetic stems having lower radii sizes, the maximum stress zone is found in the upper region of the cement mantle whilst for stems with higher radii sizes the maximum stress zone is found in the lower region of the cement mantle. For the same cement thickness, straight stems are found to produce lower maximum stress values in the cement when compared to tapered stems. Finally, for the straight models with the same cement thickness, maximum stress values are found to decrease with increasing stem radius. It can be concluded that the maximum stress values in the cement mantle decrease with decreasing cement thickness.

Hydraulic steel gates are the core adjustment mechanism for water conservancy projects, the safety of which is related to the safety of the entire water conservancy project. In this study, the issue of flow-induced vibration under the influence of pulsing water pressure when the deep-hole plane steel gate construction is partially opened is investigated using a numerical calculation approach of CFD–CSD coupling. The time-history pulsating pressure loads of each part are first determined by tracking the upstream, bottom, and downstream pulsating water pressure loads under partially open operation conditions of the gate. The impact of the water in front of the gate on the natural vibration mode and frequency of the gate is then investigated based on the analysis of the dry/wet modes of the gate structure. Additionally, the hydrodynamic load is applied to the finite element model of the gate structure while taking into account the fluid–structure coupling effect, and the results of the gate flow-induced vibration response are obtained. Three typical local opening relative openings are chosen, with the operating state of the design water head (Hs = 70 m) of a deep-hole plane steel gate as an example. According to the analysis’s findings, the gate’s natural vibration frequency is greatly lowered under the influence of the water in front of it, and its amplitude increases by 50%. The pressure value pressing on the gate changes dynamically as it is partially opened and discharged. The maximum dynamic displacement value and the maximum dynamic stress value of the gate both appear in the middle and lower part of the gate under the condition of partial opening, and both occur when the relative opening is e/H = 0.125. The maximum displacement value is 3.43 mm, and the maximum stress value is 161 MPa. The maximum dynamic displacement and dynamic stress of each gate component steadily decrease with an increase in the relative openness. The gate dynamic response analysis approach described in this research can serve as a guide for hydraulic engineering design.

In response to the phenomenon of cracking at the rivet holes of the plate connecting the rear shock absorber to the frame of the 6-meter leaf spring of the passenger bus, this article takes the rear shock absorber support and the frame as the research object. Firstly, CATIA software is used to model the object, and Hypermesh is used to divide the mesh to establish a fine element model. The Optistruct finite element solver is used to analyze the strength of the model, and the analysis results are imported into Hyperview 2019 for post-processing to analyze stress distribution and stress concentration. The simulation analysis results show that when a force of 6, 721 N is applied to the rear shock absorber support, the maximum stress value occurs at the rivet holes of the plate connecting the support to the frame, and the maximum equivalent stress value at this point is greater than the yield limit of the frame material, which is consistent with the crack location that occurs during actual vehicle operation. After adopting the strengthening scheme, the stress distribution of the frame is more uniform, greatly reducing stress concentration. The maximum stress value appears on the inner side of the right frame, and the maximum equivalent stress is less than the yield limit of the frame material, avoiding the crack phenomenon. The results indicate that this scheme can not only meet the performance requirements but also provide a reference for structural improvement and optimization design of the connection between the rear shock support and the frame.

This study presents effects of gender on the elastic mechanical properties of human abdominal fascia according to direction of loading. Samples from umbilical fascia (UF) have been cut along the fibres direction or perpendicular to them. The uniaxial tensile tests were performed. The mean curves of UF according to gender and direct of loading were presented. Mean values of the maximum tensile stress, stretch at maximum stress, maximum stretch ratio and elastic modulus E calculated at 5% strain were determined from the obtained stress – stretch ratio. The differences between investigated behaviour of male and female samples were distinguished. The maximum tensile stress for female samples was 1.1 MPa at transversal direction and 2.9 MPa at longitudinal direction, while for male samples the maximum tensile stress was 0.5 MPa and 1.5 MPa accordingly. The obtained results show that there exists statistically significant differences between values of maximum stress and elastic modulus E5 according to gender and direction of loading.

The most commonly accepted method in evaluation of the mechanical properties of metals would be the tension test. Its main objective would be to determine the properties relevant to the elastic design of machines and structures. Investigation of the engineering and true Stress-strain relationships of three specimens in conformance with ASTM E 8 - 04 is the aim of this paper. For the purpose of achieving this aim, evaluation of values such as ultimate tensile strength, yield strength, percentage of elongation and area reduction, fracture strain and Young's Modulus was done once the specimens were subjected to uniaxial tensile loading. The results indicate that the properties of steel materials are independent from their thickness and they generally yield and fail at the same stress and strain values. Also, it is concluded that the maximum true stress values are almost 15% higher than that of the maximum engineering stress values while the maximum true strain failure values are 1.5% smaller than the maximum engineering strain failure values.

A three-dimensional finite-element stress analysis and strength evaluation of stepped-lap adhesive joints subjected to static tensile loadings

Scarf adhesive joints used in practice. However, the stress distributions and the joints strengths have not yet been fully elucidate. Important issues are how to determine the scarf angle in adherend and how to determine the adhesive properties. In this study, the stress distributions in scarf adhesive joints under static tensile loadings are analyzed using three-dimensional finite-element calculations. In the FEM calculations, the effects of Young's modulus of the adhesive, adhesive thickness, scarf angle of the adherend on the stress distributions at the adhesive interfaces are examined. The maximum principal stresses were calculated at every element at the interfaces. As the results, it is found that the maximum value of the maximum principal stress occurs at the edge of the adhesive interfaces (z=0, 1/s=1). It is also observed that the maximum value of the stress is the smallest, when the scarf angle is 60 degree. In addition, the joint strength is estimated using the interface stress. For the verification of the FEM calculations, the experiments were carried out to measure the strengths and the strains in the joints under static tensile loadings using strain gauges. Fairly good agreements are observed between the numerical and the measured results concerning the joint strength and the strains.

The stress distributions in scarf adhesive joints of dissimilar adherends under static bending moments are analyzed using three-dimensional finite-element calculations. The code employed is ANSYS. In FEM calculations, the effects of Young’s modulus of the adhesive, adhesive thickness, scarf angle of the adherend on the stress distributions at the adhesive interface are examined. As the results, it is found that the maximum value of the maximum principal stress occurs at the edge of the scarf adhesive interface. It is also observed that the maximum value of the stress is minimum, when the scarf angle is 60 degree. In addition, the joint strength is estimated using the obtained stress distribution. For the verification of the FEM calculations, the experiments were carried out to measure the strengths and the strains in the joints under static bending moments using strain gauges. Fairly good agreements are observed between the numerical and the measured results concerning the joint strength and the strains.