•A new bistable piezoelectric harvester with simplified preloading mechanism is designed.•Bistability is realized by combining elastic and gravitational potential energies.•Potential energy traps ...have less inconsistency for easy skipping between two energy wells.•A figure of merit is introduced for performance comparison versus existing designs.•Results show the efficiency of proposed device for scavenging energy in gravity direction.
This paper presents the design, fabrication, and testing of a novel bistable piezoelectric energy harvester dedicated to vibration energy harvesting in the direction of gravity. Its unique feature is that the bistability is realized by combining the elastic potential energy of a bridge-type compliant mechanism and the gravitational potential energy of a proof mass together, which simplifies the preloading mechanism design. As a result, its potential energy traps exhibit less inconsistency under the excitation in gravity direction, which leads to easier skipping between the two energy wells. To evaluate the performance of the proposed harvester, the analytical model is established. Parametric study is conducted to investigate the influence of the structural parameters on the harvester’s performance. Static structural analysis is performed to predict the actual performance of the proposed harvester, which is verified by conducting simulation studies. A prototype device was fabricated for experimental testing. In addition, a figure of merit has been introduced for performance comparison versus existing designs. Experimental results indicate that the proposed device is more suitable for scavenging the energy in gravity direction.
One of the promising objects for application in architectural and construction practice are analytically determined structural shapes in the form of thin elastic shells with a median surface in the ...form of algebraic ruled surfaces on a rhombic plan on the basis of various curves. In particular, this study considers three surfaces with identical framework forming lines of superellipses using framework curves that have the appearance of waterline, midships section, and main buttock lines - lines that have been initially generated and used in shipbuilding. The shapes of structures on a rhombic base were considered. The study contains geometric modeling of such structures, creation of finite element models and their computation. A comparison of the values characterizing the stress-strain state for three different shapes with the same span and lifting arm (variant designing with optimized choice) has been carried out. From the theoretical point of view, the possibility of generating three different surfaces on the same frame seems to be an interesting result. From the viewpoint of strength analysis, one of the three obtained shells was chosen as it has the most uniform stress distribution, which is the most economical in terms of material cost.
In the present work, a reconfigurable leaf drill jig is developed in order to reduce the time for production, accurate and precise drilling operation. The component chosen for our study is ...clutch-pressure plate made of cast iron material which is being used in the clutch system for manual transmission. At the top of the component 10 circular holes with36° equi-spaced were designed. C45 steel was chosen to be the jig material due as an alternative to alloy steel.The novelty of this work is that a sliding vee block is used in the base plate to accommodate various sizes of pressure plate. Full jig design assembly along with various parts and exploded view were shown. The workpiece deformation during clamping is estimated using static structural analysis(ANSYS) and is found to be negligible.The sliding Vee block locator and other parts of jig were also subjected to static structural analysis and the design of jig is found to be safe.
Abstract
The camber angle is one of the wheel alignment properties that is crucial as a slight change to the orientation of the camber angle determines the lifespan of a tire. The stress distribution ...on the innermost of a tire increase as the positive camber angle is increased, and vice versa, which causes the abnormal uneven premature wear of the tire. This research is done with the main objectives to simulate the performance of tires concerning the camber angle by using the finite element analysis method, and to study the influence of camber angle on different tire tread patterns under two different road conditions, i.e., smooth road and irregular road. Three tire models with different tire tread patterns and two different road conditions are developed using SolidWorks while the investigation of each tire performance is done through ANSYS under static condition in this research. Tire inflation analysis is performed using static structural analysis feature available in ANSYS where the total deformation and equivalent stress are determined based on the specific vertical load applied onto the tire, ignoring any damping effects and inertia. Boundary conditions and other relevant constraints are applied, and then mesh independent test is carried out to all tire models prior to performing the simulation. Based on the simulation results, the maximum total deformation increases as the camber angle increases in both road conditions, while the maximum equivalent stress does not show any trend. It is concluded that tire tread pattern influences the maximum equivalent stress experienced by the tire.
Abstract Mars rovers are developed using the most sophisticated technology. Competitions such as the University Rover Challenge (URC), European Rover Challenge (ERC), and Anatolian Rover Challenge ...(ARC) encourage students to become acquainted and experienced with cutting-edge technology. This paper focuses on the development and analysis of a modified version of a non-pneumatic tire (NPT) for the MIST Mars rover “Phoenix 2.0.” Recent studies show that NPT has a good potential to replace conventional tires. To optimize the tire design for the rover, many design aspects are considered. The additive manufacturing process is used to fabricate the tire model to ensure the proper geometrical shape and usage of material. Later, a static structural analysis is conducted to investigate the stress and deformation of the tire that it may experience during rover operation. The developed deformation and stress in this analysis are well protected by the honeycomb structures that are optimized from many design attempts. The result shows a positive indication of meeting the desired criteria that eventually results in the fabrication of the tire and participation in the ARC competition. This research will inspire others to contribute to the advancement of NPT in various circumstances where pneumatic tires perform inadequately.
•Transient thermo-mechanical analysis of a typical small gas turbine engine is done.•Blade tip clearance influenced by the deformation of turbine stage components is estimated.•Coupled transient ...thermal-structural analysis was performed on three-dimensional model.•Analysis is performed considering highly non-linear properties of material.•High-temperature gradients contribute largely to the radial displacement of the blade.
Turbine blade tip clearance is one of the significant factors that influence turbine efficiency, Specific Fuel Consumption (SFC), Exhaust Gas Temperature (EGT), and emissions. Controlling these parameters in a small gas turbine engine (SGT) is a challenging task due to small blade height and viscous working environment. SGT are subjected to high-temperature gradients at the combustor outlet, which affects the turbine blade tip clearance. This paper presents the thermo-mechanical analysis of a typical SGT engine to study the blade tip clearance influenced by the deformation of turbine stage components (turbine rotor, nozzle guide vane (NGV) with integral blade shroud) during transient phases. ANSYS Workbench is used to perform transient thermal and structural analyses. The structural analysis is performed taking the material properties to be temperature-dependent. The SGT engine under consideration operates at a design speed of 45,000 rpm. Initially, steady-state thermal analysis and static structural analysis were carried out to understand the structural behaviour of the system under a thermal and centrifugal loading environment. Since different components of the engine assembly operate at different temperatures, the effects of convection and conduction at the interfaces influence the radial clearances between the static and rotating parts of the engine. A one-way coupled transient thermal-structural analysis was performed on a three-dimensional model to capture the actual behaviour of the tip clearance during transient operating conditions. Significant growth of blade and rotor was observed relative to the casing resulting in minimal clearances during these transient operations. Hence, it is important to estimate desired cold clearance, considering transient phenomena, to avoid mechanical blade rub with the shroud. It is observed that high-temperature gradients contribute primarily to the stresses and radial displacement of the rotor compared to centrifugal effects. The turbine rotor takes more time (t = 600 s) to reach steady-state temperatures compared to NGV (t = 120 s) due to the solid mass of the disc. The location and magnitude of maximum and minimum equivalent stress changes with time in NGV and rotor, and they experience maximum stress at the initial time steps compared to steady-state.
Abstract
All-terrain vehicle (ATVs) is a mature and well-cultivated product with prominent significance all over the world. As these products are made to be driven by hoonigans, safety is the main ...matter of concern. This research paper conducts a crash test analysis on an All- Terrain Vehicle (ATV) chassis to evaluate its structural integrity and occupant safety during collisions. Using advanced computational modeling and finite element analysis, various crash scenarios like Frontal and Side impact crash (considering the driver’s weight) with a wall, Modal analysis, and Static structural analysis are simulated. The 3D finite element model considers material properties and geometry, analyzing acceleration, displacement, deformation, and stress distribution within the chassis. The study assesses the chassis’s ability to absorb impact energy and protect occupants, examining the effectiveness of safety features like roll cages and seat restraints
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