Untitled Quiz

The course explores the significance of defining design problems, methodologies employed, and contextual factors influencing mechanical engineering solutions.
The course focuses on mechanical engineering design problems.
Design problems are complicated and require understanding of technical requirements, constraints, and the broader environmental context.

The course includes minor, major, lab, project, and attendance components.
The attendance policy offers 4 marks for attendance greater than or equal to 75%, 0 marks for attendance less than 50%, and a linear variation between 0-4 marks for attendance ranging from 50-75%.
Each lab (of 13 classes) counts towards 2% of the total lab marks.
The project includes design and optimization of a gearbox (components and assembly) for a specific application.
The pass criterion for auditing the course is achieving a mark greater than 40.

The environmental impact of car tires over their lifetime can be assessed using Life Cycle Impact Assessment (LCIA) methodologies.
Manufacturing a car tire generates approximately 0.5 kilograms of trash.
Using manufacturer data, 3,000 liters of fuel are required for a car traveling 50,000 kilometers.
Each tire consumes 750 liters of fuel.
The eco-index for the manufacture, usage, and recycling of an automobile tire over its entire life cycle is determined to be 153 Pt, with a standard deviation of 37.2 Pt.

Advances in materials, manufacturing techniques, and computing constantly change mechanical design.
Environmental impact and sustainability are growing concerns and require designs to consider energy efficiency, recyclability, and a minimal ecological footprint.
Regulatory and safety standards are updated over time to ensure products meet legal requirements and are safe and reliable.
Finally, design solutions must be cost-effective.

The South-Pointing Chariot was a two-wheeled vehicle equipped with a movable pointer that indicated south.
It utilized rotating road wheels to operate a geared mechanism that kept the pointer aimed south.
The mechanism was prone to cumulative errors and uncertainties due to manual alignment and the rotation of the pointer to counteract turns.

With the introduction of the differential gear mechanism, the concept of bevel gears was developed.
The emergence of form cutters and gear hobbing machines allowed for mass-production and refinements in gear form and performance.
In 1897, Herman Pfauter invented a machine capable of cutting both traditional "spur" gears and helical gears.
Modern 6-axis machines have perfected the design, cutting, and manufacturing of gears.

Different gear types (spur, helical, bevel, worm) are designed for specific applications.
Helical gears are quieter and offer less vibration compared to spur gears.
Bevel and worm gears have more complex designs than spur gears.
American Gear Manufacturers Association (AGMA) provides detailed data and algorithms for gear calculations.

Crossed helical gears are mounted on shafts that are neither parallel nor intersecting.
They connect shafts at an angle between 45 and 90 degrees.
They are used in light-load applications, such as distributor and speedometer drives in automobiles.
They are less efficient than parallel helical gears.

Additive manufacturing (3D printing) technology enables the production of complex gear geometries.
Future trends include integrating sensors and IoT technology into gears for real-time monitoring and predictive maintenance.
New coatings are being developed to enhance gear performance in extreme environments.

Mesh misalignment occurs when the axial position of the meshing surfaces shifts due to deflections or manufacturing errors in the gears and housings.
This can lead to large stresses and increased noise in a gear pair.
Mesh misalignment can be categorized into three types: parallel misalignment, radial misalignment, and angular misalignment.

A higher contact ratio (k > 1) indicates a "long addendum gear" with increased tooth contact.

Plastic gears offer various advantages: low noise, corrosion resistance, lightweight, low inertia, and cost-effectiveness.
The plastic forming process during manufacturing often leads to low precision due to shrinkage, resulting in non-standard tooth profiles and errors.
Three main aspects are considered to address minimum tip thickness problems in small gears:
- Relationship between plastic gear tooth root modification and rack tool tip modification
- Relationship between plastic gear tooth tip modification and rack tool root modification
- Controllable coating to avoid residual tensile stresses and thermal distortion.
The performance of Nylon/Steel gear pairs is better than Nylon/Nylon pairs due to the difference in coefficient of friction.

Four types of gear lubricants are commonly used:
- Rust and oxidation-inhibited oils
- Compounded gear oils
- EP gear oils
- Synthetic gear oils

Spherical gears find applications demanding complex motion and high flexibility, making them suitable for robotics, aerospace mechanisms, and advanced machinery.

This section discusses the transition from solid structures to fragmented or finely dispersed media in gear design.
Magneto-rheological finishing (MRF) is a polishing technique that achieves sub-nanometer levels.
MEMS (Micro-Electro-Mechanical Systems) and NEMS (Nano-Electro-Mechanical Systems) are emerging technologies in gear design.
MRF "polishing tools" never dull or change and adapt to complex shapes.
MRF produces high removal rates, leading to shorter processing times.