Numerical and Experimental Investigations on the Effects of Variable Cavity Pressure on the Formability of GLARE Using Hydromechanical Deep Drawing

Excellent physical and mechanical properties of fiber metal laminates (FMLs) have made them a very popular and most suitable material to make high strength and lightweight products in different industries for example automobile, military, and aerospace. Glass fiber aluminum reinforced epoxy (GLARE) is one of the most used fiber metal laminate among the family of fiber metal laminates, but there are some challenges in its formability. Our study mainly focuses on the formability of the GLARE cup parts by using hydromechanical deep drawing. Forming depth with good quality (without any wrinkling, delamination, or fracture), failure mode analysis and wall thinning rate (%) distribution of the parts are the main criteria in the formability. The influence of variable cavity pressure (VCP) with respect to punch strokes had been investigated by using numerical simulations and experiments. Results showed that the variable cavity pressure in case of increasing or decreasing the cavity pressure had very much effect on the formability. Stepwise increasing the VCP with respect to punch strokes resulted in a maximum forming depth of 29.00mm as well as good quality whereas in the case of stepwise decreasing the variable cavity pressure, results were not encouraging. Commercially available code ABAQUS explicit was used for finite element analysis simulation which had shown close agreement with the experimental results.

Push-Out Test and FEM Analysis of Continuous Shear Connector

Composite steel concrete bridges with embedded continuous shear connectors are one of the newer popular options for short span (up to 20 m) bridges. They can be used for both road and railway bridges and due to their low structural height, nowadays, they are also a welcome alternative for bridge reconstructions – the concrete part serves as the bridge deck as well as the main structure. Unfortunately, In the Slovak Republic, no such bridges have been built as of yet (2020). At Technical University of Kosice, Department of Steel and Timber Structures, an extensive research regarding the steel shear connectors have been launched. Its goals are to bring new, easier for construction (due to prefabrication process), more resistant with even lower structural height, and more economical (due to lesser usage of materials and quick construction) geometrical solutions for composite steel concrete bridges as well as to open and popularize this solution for developers in the Slovak Republic. In this article, one of the new types is presented. It has a cross-section in a shape of a trapezoid, with holes in all its sides, except the bottom flange. Their purpose is to create concrete studs and secure full shear transmission with higher shear resistance, but they also serve to create space for transverse reinforcing bars. Its geometrical and material characteristics are closely specified. Results and process of push-out tests performed in Laboratory of Excellent Research onto three specimens are described and compared to results of finite element analysis simulation performed in Abaqus software.

Numerical Analysis of Fire Water Storage Tank under Seismic Loading

Maintenance and continuously monitoring the condition of above ground storage tanks are significant when the tanks are placed in service. The American Petroleum Institution (API) 653 and other international codes provides the minimum requirements for inspection & maintaining the integrity of tanks during its service. The tank settlement is one of the major threats for tank’s integrity. In this paper, a storage tank is assessed for uniform settlement under various loading condition such as seismic, dead load, static load, corrosion loss of shell plate etc. In the present study, a finite element model is designed with uniform settlement condition and study of its governing hoop stress at shell plate has been carried out under different loading conditions. A fire water storage tank (constructed with IS 2060 GR. B material) and different seismic zones in India are taken for this study. The finite element analysis simulation shows that increase of hoop stress in the bottom shell course due to uniform settlement, the decrease in plate thickness and with different seismic active regions. Moreover, the maximum stresses have been observed at shell bottom course (close to bottom plate).

Effect of Mesh Density on Finite Element Analysis Simulation of a Support Bracket

Investigation on the effect of mesh density on the analysis of simple support bracket was conducted using Finite element analysis simulation. Multiple analyses were carried out with mesh refinement from coarse mesh of 3.5 mm to a high-quality fine mesh with element size of 0.35 mm under 15 kN loading. Controlled mesh analysis was also conducted for the same loading. At the mesh size of 0.35 mm, it has a maximum stress value of 42.7 MPa. As the element size was reduced, it was observed that below 1.5 mm (higher mesh density) there was no significant increase in the peak stress value; the stress at this level increased by 0.028 % only. Further decreased of mesh size shows insignificant effect on the stresses and displacements for the high-quality fine mesh analysis. The application of High-quality mesh control analysis showed a significant reduction in the computation time by more than 90%. Regardless of the reduction in computation time, the controlled mesh analysis achieved more than 99% accuracy as compared to high-quality fine mesh analysis. Keywords— Computation time, Finite Element Analysis, Mesh density, Support Bracket.

Effect of Glass Bubbles on Friction and Wear Characteristics of PDMS-Based Composites

The purpose of this study is to improve the mechanical durability and surface frictional characteristics of polymer/ceramic-based composite materials. Polydimethylsiloxane (PDMS)/glass bubble (GB) composite specimens are prepared at various weight ratios (PDMS:GB) by varying the amount of micro-sized GBs added to the PDMS. The surface, mechanical, and tribological characteristics of the PDMS/GB composites are evaluated according to the added ratios of GBs. The changes in internal stress according to the indentation depth after contacting with a steel ball tip to the bare PDMS and PDMS/GB composites having different GB densities are compared through finite element analysis simulation. The elastic modulus is proportional to the GB content, while the friction coefficient generally decreases as the GB content increases. A smaller amount of GB in the PDMS/GB composite results in more surface damage than the bare PDMS, but a significant reduction in wear rate is achieved when the ratio of PDMS:GB is greater than 100:5.

Improving the Solder Joint Reliability Prediction Accuracy for Quad Flat No Lead Packages

This paper discusses the modeling approach used in improving the solder joint reliability prediction for Quad Flat No Lead (QFN) packages. A new power equation fatigue prediction model was developed based on the accumulated creep strain energy density from FEA (finite element analysis) simulation and the corresponding actual experimental result in terms of solder characteristic life of different QFN packages. The new curve fitted fatigue life correlation equation was then used in the solder joint reliability modeling together with the use of a hyperbolic sine constitutive model for lead-free solder. The model prediction using the new curve fitted equation was compared with the result from using the equation previously published. Based on the results, the new curve-fitted life prediction equation was able to improve the accuracy of solder life prediction. This study shows that solder joint reliability prediction could be improved by developing a prediction model based on actual data and consistent FEA modeling considerations in terms of methodology, material model and properties.

Design and Analysis of Dual Mover Multi-Tooth Permanent Magnet Flux Switching Machine for Ropeless Elevator Applications

A dual mover yokeless multi-tooth (DMYMT) permanent magnet flux switching motor (PM-FSM) design is presented in this article for ropeless elevator applications. The excitation sources, including a field winding and permanent magnet, are on the short mover in the proposed design structure, whereas the stator is a simple slotted iron core, thus reducing the vertical transportation system cost. The operational principle of the proposed DMYMT in PM-FSM is introduced. The proposed dual mover yokeless multi-tooth Permanent Magnet Flux Switching Motor is analyzed and compared for various performance parameters in a Finite Element Analysis package. The proposed machine has high thrust force and cost-effectiveness compared to conventional dual permanent magnet motor. Finally, this paper also develops an analytical model for the proposed structure, validated by comparing it with Finite Element Analysis simulation results. Results show good agreement between analytical prediction and Finite Element Analysis results.

Stress and Fatigue Analysis of Picking Device Gears for a 2.6 kW Automatic Pepper Transplanter

A seedling picking device is an essential component for an automatic transplanter to automatically convey the seedling to the dibbling part. It is necessary to find the appropriate material and dimensions for the picking device gears to avoid mechanical damage and increase their durability. Therefore, the objectives of this research were to analyze the stress of a picking device gear mechanism in order to select suitable materials and dimensions, and to predict the fatigue life by considering the damage level. The picking device gear shaft divided the input power into two categories, i.e., crank and cam gear sets. Finite element analysis simulation and American Gear Manufacturers Association standard stress analysis theory tests were conducted on both of the crank and cam gear sets for different materials and dimensions. A test bench was fabricated to collect the load (torque) data at different gear operating speeds. The torque data were analyzed using the load duration distribution method to observe the cyclic load patterns. The Palmgren–Miner cumulative damage rule was used to determine the damage level of the picking mechanism gears with respect to the operating speed. The desired lifespan of the transplanter was 255 h to meet the real field service life requirement. Predicted fatigue life range of the picking mechanism gears was recorded as from 436.65 to 4635.97 h, making it higher (by approximately 2 to 18 times) than the lifespan of the transplanter. According to the analyses, the “Steel Composite Material 420H carbon steel” material with a 5 mm face width gear was suitable to operate the picking device for a 10-year transplanter service life. The analysis of stress and fatigue presented in this study will guide the design of picking device gears with effective material properties to maintain the recommended service life of the pepper transplanter.

Loading comparison of two structures in the moving tube of a non-invasive prosthesis

BACKGROUND: The treatment of adolescent patients with distal femoral cancer has always been a concern. The limb-salvage, regarded as a mainstream treatment, had been developed in recent years, but its application in children still remains challenging. This is because it can lead to potential limb-length discrepancy from the continued normal growth of the contralateral lower body. The extendable prosthesis could solve this problem. The principle is that it can artificially control the length of the prosthesis, making it consistent with the length of the side of the lower limbs. However, this prosthesis has some complications. The extendable prosthesis is classified into invasive and minimally invasive, which extends the prosthesis with each operation. OBJECTIVE: We designed a new non-invasive prosthesis that can be extended in the body. Based on the non-invasive and extendable characteristics, we need to verify the supporting performance of this prosthesis. METHODS: We carried out a mechanical testing method and finite element analysis simulation. CONCLUSION: The support performance and non-invasively extension of this prosthesis were verified.

Development of V-Shaped Beam on the Shock Resistance and Driving Frequency of Micro Quartz Tuning Forks Resonant Gyroscope

The application of gyroscopes in harsh environments has always been a hot topic. As a high-quality material for manufacturing gyroscopes, quartz crystals need to be designed and optimized to meet the normal operation of gyroscopes in harsh environments. The Micro Electronics Mechanical System(MEMS) quartz tuning forks resonant gyroscope is one of the quartz gyroscopes. The elastic structure (V-shaped beam) between the anchor support point and tuning forks plays a vital role in the MEMS quartz tuning forks resonant gyroscope. This structure determines the natural frequency of the gyroscope, and more importantly, determines the shock resistance of the gyroscope structure. In this article, the MEMS quartz tuning forks gyroscope with different V-shaped beam thicknesses are simulated and analyzed by finite element analysis simulation software. After the modal analysis and shock simulation (the half-cycle sine shock pulse with amplitude of 1500 g (g is the acceleration of gravity) and duration of 2 ms in the six shock directions), the results show that when the beam thickness is 80 μm, the maximum stress is 94.721 MPa, which is less than the failure stress of quartz crystal. The gyroscope’s shock resistance is verified through shock testing.