Mse300 ppt
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The document analyzes the potential application of aluminum in the lander of the Mars Rover II, focusing on the egress phase and associated design considerations. It discusses the landing sequence, the structural requirements for the lander petals and ramps, and presents a methodology for understanding the relationship between grain size and the mechanical properties of metals. Findings indicate that a combination of small and large grains can optimize yield strength and Young's modulus for material selection.
Mse300 ppt
- 1. Material for the Egress Phase: Critical Analysis of Aluminium for Possible Applications in Lander of Mars Rover-II Aditya Shankar (12052) (Methology) Archit Agrawal (12153) (Suggestions) Semanti Mukhopadhyay (12645) (Introduction) Shivam Tripathi (12676) (Discussion and Conclusions)
- 2. For Science is Nothing but Perception.. --Plato
- 4. Mission Timeline • Pre-Launch: Preparation for the mission, landing site selection, assembly and testing, and delivery to Sri Harikota • Launch: Lift-off from Earth • Cruise: Voyage through space • Approach: Nearing the red planet Mars • Entry, Descent, and Landing: Journey through the martian atmosphere to the surface • Rover Egress: Leaving the lander to begin exploration • Surface Operations: Learning about Mars through the day-to-day activities of the rovers4 Image source: http://mars.isro.gov/mer/mission/images/merl4.jpg
- 5. Landing/Egress Sequence • An aeroshell and a parachute decelerate the lander through the Martian atmosphere. • Prior to surface impact, retro-rockets are fired to slow the lander´s speed of descent, and airbags are inflated to cushion the lander at surface impact. • After its initial impact, the lander bounces along the Martian surface until it rolls to a stop. • The airbags are then deflated and retracted, and the lander petals and rover egress aids are deployed. • Once the petals have opened, the rover deploys its solar arrays, and places the system in a safe state.
- 6. Lander Design • The component of main importance in the Lander Petal. • Lander Petal: Retraction system that slowly drag the airbags • toward the lander to get them out of the path of the rover. • Small ramps or “ramplets”, connected to the petals fan out and create "driving surfaces" that fill in large spaces between the lander petals. • Ramplets nicknamed “Batwings”
- 7. Motivation for Present Work • Ramplet Design: Requisite Properties • Strong enough to bear shock and stress during landing at low temperatures. • Must be able to cover dangerous, uneven terrain, rock obstacles, and leftover airbag material that could get entangled in the rover wheels. • The rover must not succumb to stresses even when it bangs its belly on a rock or smashes into the ground as it was moving off the lander. • Resistance to collision by high speed particles in atmosphere • Withstand extreme temperatures. Material Under Scrutiny: Metals!! Metal Required?? High Stiffness, High Ductility, Low Specific Volume, High Strength, High Impact Toughness Processing Required?? Grain Size Engineering
- 8. Effect of grain size on the Yield strength and Young’s modulus of elasticity of metallic material • Producing a relationship between grain size and yield strength of metallic material by Hall-Petch equation.
- 9. Methodology: • 1)Sample Preparation: • Firstly we need to prepare samples with a range of different grain size, d. • We will do this by deforming (rolling) a plate by different amount, cutting samples at each stage.
- 10. Methodology: 2)Vickers Hardness Test: • We will then anneal the sample to fully recrystallize them. • Heavily deform samples should recrystallize to a final grain size • After measuring a grain size , We will do Vicker’s Hardness measurements on each , and convert hardness to yield stress and will end up with a relationship between grain size and yield strength and Young’s modulus of elasticity
- 11. Observation: Grain Size d(micrometre) Yield Stress (Mpa) 3.4 365.0 5.6 343.2 11.2 269.6 21.0 240.4
- 12. Discussion And Conclusion: • We need materials having High Stiffness, High Ductility, Low Specific Volume, High Strength, High Impact Toughness • As per experiment lower the grain size higher will be the yield strength • Also firstly Young’s modulus of elasticity will increase linearly with grain size and will constant after a critical value.
- 13. Suggestions : • So to have a good Young’s modulus and yield strength we should fabricate a material having both type of grains (small and large both). • Smaller grains provide restriction to movement of dislocation and yield strength increases and large grains will provide a good Young’s modulus
- 14. Thank You!