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Technical Paper

The irrotational intensity: an efficient tool to understand the vibration energy propagation in complex structures using an FE Model.

2024-06-12
2024-01-2942
Although structural intensity was introduced in the 80's, this concept never found practical applications, neither for numerical nor experimental approaches. Quickly, it has been pointed out that only the irrotational component of the intensity offers an easy interpretation of the dynamic behavior of structures by visualizing the vibration energy flow. This is especially valuable at mid and high frequency where the structure response understanding can be challenging. A new methodolodgy is proposed in order to extract this irrotational intensity field from the Finite Element Model of assembled structures such as Bodies In White. This methodology is hybrid in the sense that it employs two distinct solvers: a dynamic solver to compute the structural dynamic response and a thermal solver to address a diffusion equation analogous to the thermal conduction built from the previous dynamic response.
Technical Paper

Surface Properties of Shot-Peened and Plasma Sprayed Powder-Coated Alpha-Beta Titanium Alloy Implants

2024-05-15
2024-01-5060
The paramount importance of titanium alloy in implant materials stems from its exceptional qualities, yet the optimization of bone integration and mitigation of wear and corrosion necessitate advanced technologies. Consequently, there has been a surge in research efforts focusing on surface modification of biomaterials to meet these challenges. This project is dedicated to enhancing the surface of titanium alloys by employing shot peening and powder coatings of titanium oxide and zinc oxide. Comparative analyses were meticulously conducted on the mechanical and wear properties of both treated and untreated specimens, ensuring uniformity in pressure, distance, and time parameters across all experiments. The outcomes underscore the efficacy of both methods in modifying the surface of the titanium alloy, leading to substantial alterations in surface properties.
Magazine

Aerospace & Defense Technology: May 2024

2024-05-09
Explaining MOSA from the Team that Led the Army Aviation Mission Computing Environment Task Order What's the Best DC Motor for Your Commercial Aerospace Application? Aerospace Production: Overcoming Challenges in Composite Machining Understanding the Limits of Artificial Intelligence for Predictive Maintenance Pushing the Limits: Engineering Advanced RF Interconnects to Meet the Challenges of Hypersonic Missile Development Expanding Possibilities for Superconducting Qubits With Niobium Researchers Help Robots Navigate Efficiently in Uncertain Environments A new algorithm reduces travel time by identifying shortcuts a robot could take on the way to its destination.
Journal Article

Experimental Analysis of Heat Transfer Post Quenching of Medium Carbon Steel

2024-05-08
Abstract Transient temperature analysis is involved in the thermal simulation of the heat treatment process, in which the hot metal temperature changes with respect to time from an initial state to the final state. The critical part of the simulation is to determine the heat transfer coefficient (HTC) between the hot part and the quenching medium or quenchant. In liquid quenching, the heat transfer between the hot metal part and water becomes complicated and it is difficult to determine HTC. In the current experimentation a medium carbon steel EN 9 rod with a diameter of 50 mm and length 100 mm was quenched in water and ethylene glycol mixture with different concentrations. A part model was created; meshed and actual boundary conditions were applied to conduct computational fluid dynamics (CFD) analysis. In order to validate CFD analysis the experimental trials were conducted.
Technical Paper

Anti-Rollover Control for All-Terrain Vehicle Based on Zero-Moment Point

2024-04-30
2024-01-5055
To investigate the rollover phenomena experienced by all-terrain vehicles (ATVs) during their motion caused by input from the road surface, a combined simulation using CarSim and Simulink has been employed to validate an active anti-rollover control strategy based on differential braking for ATVs, followed by vehicle testing. In the research process, a nonlinear three-degrees-of-freedom vehicle model has been developed. By utilizing a zero-moment point index as a rollover warning indicator, this approach could accurately detect the rollover status of the vehicle, particularly in scenarios involving low road adhesion on unpaved surfaces, which are characteristic of ATV operation. The differential braking, generating a roll moment by adjusting the amount of lateral force each braked tire can generate, was proved as an effective method to enhance rolling stability.
Technical Paper

Influence of Machining Parameters on Tungsten Carbide Inserts in ANSYS Analysis of Maraging Steel Machining

2024-04-29
2024-01-5057
The machining process is employed to transform a workpiece into a predefined geometry with the assistance of a cutting tool. Throughout this process, the cutting tool undergoes various adverse effects, including deformation, stress, thermal gradient, and more, all of which impact tool sharpness, surface finish, and tool life. These outcomes are also influenced by cutting parameters, specifically cutting speed, feed rate, and depth of cut. The present investigation aims to demonstrate the application of ANSYS analysis software in predicting stress, deformation, thermal gradient, and other factors on the tool insert tip for various machining parameters. To achieve this, an experimental setup was arranged to collect cutting force and temperature data using a dynamometer and thermocouples during the machining process of maraging steel with a tungsten carbide tool insert. Experiments were conducted with different combinations of machining parameters using design of experiments (DoE).
Standard

Aluminum Alloy, Extruded Profiles (2395-T84), 3.95Cu - 1.15Li - 0.3Ag - 0.5Mg - 0.1Zr, Solution Heat Treated, Stress Relieved by Stretching, and Aged

2024-04-25
CURRENT
AMS4359A
This specification covers an aluminum alloy in the form of extruded rods, bars, and profiles (shapes) 0.040 to 1.500 inches (1.02 to 38.10 mm), inclusive, in thickness, and produced with maximum cross-sectional area of 23.25 square inches (15000 mm2) and a maximum circumscribing circle diameter (circle size) of 15.5 inches (394 mm) (see 2.4.1 and 8.6).
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