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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

Development of Deployment Mechanism for RAMBHA-LP Payload Onboard Chandrayaan-3 Lander

2024-06-01
2024-26-0455
RAMBHA-LP (Radio Anatomy of Moon Bound Hypersensitive Ionosphere and Atmosphere - Langmuir Probe) is one of the key scientific payloads onboard the Indian Space Research Organization’s (ISRO) Chandrayaan-3 mission. Its objectives were to estimate the plasma density and its variations on the near lunar surface. The probe was initially kept in a stowed condition attached to the lander. A mechanism was designed and realized to meet the functional requirement of deploying the probe at a distance of 1 meter, equivalent to the Debye length of the probe in the moon’s plasma environment. The probe deployment mechanism consists of the Titanium alloy spherical probe with a Titanium Nitride coating on its surface to achieve a constant work function, a long carbon-fiber-reinforced polymer boom, a double torsion spring, a dust-protection box, and a shape-memory alloy-based Frangibolt actuator for low-shock separation. The entire mechanism weighed less than 1.5 kilograms.
Standard

Rings, Retaining – Spiral Wound, Uniform Section Corrosion and Heat Resistant, UNS S66286

2024-04-10
CURRENT
AS4299B
This procurement specification covers retaining rings of the spiral wound type with uniform rectangular cross-section, made of a corrosion and heat resistant age hardenable iron base alloy of the type identified under the Unified Numbering System as UNS S66286, work strengthened and heat treated to a tensile strength of 185 to 240 ksi at room temperature.
Standard

Steel, Corrosion- and Heat-Resistant, Bars, Wire, Forgings, Mechanical Tubing, and Stock for Forging and Heading, 15Cr - 25.5Ni - 1.2Mo - 2.1Ti - 0.006B - 0.30V (Alloy A286), Consumable Electrode Remelted, 1650 °F (899 °C) Solution Heat Treated

2024-04-10
CURRENT
AMS5734L
This specification covers a corrosion- and heat-resistant steel in the form of bars, wire, forgings, mechanical tubing up to 5.00 inches (127 mm), inclusive, in nominal diameter or least distance between parallel sides (thickness), and stock for forging or heading.
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