Welcome to "Factors Influencing Design of Solutions"!
In this chapter, we are going to look at the "behind-the-scenes" decisions engineers have to make. Designing a product isn't just about making it look good; it’s about choosing how it’s powered, how long it will last, and how easy it is to fix. Think of it like choosing a car: you don’t just look at the color, you look at the fuel it uses, how often it needs a service, and if you can actually afford the parts!
1. Powering Your Design: Energy Production
Every engineered solution needs energy to be built and, often, energy to work. Engineers must weigh the benefits (the good stuff) against the drawbacks (the bad stuff) for different energy sources.
Renewable Energy (Green Energy)
These sources won't run out and are generally better for the environment.
• Wind: Uses turbines to catch the wind. Example: Large wind farms in the North Sea.
Benefit: No greenhouse gases. Drawback: Doesn't work if it’s not windy!
• Solar: Uses panels to turn sunlight into electricity.
Benefit: Great for remote areas. Drawback: Expensive to set up and needs sun.
• Tidal: Uses the movement of the ocean tides.
Benefit: Very predictable (tides happen every day!). Drawback: Can damage local sea life and is expensive to build.
• Biomass: Burning organic materials like wood or plant waste.
Benefit: Uses up waste products. Drawback: It still releases some CO2 when burned.
Non-Renewable and Nuclear
• Fossil Fuels: Coal, oil, and gas.
Benefit: Reliable and currently easy to get. Drawback: Major cause of global warming and will eventually run out.
• Nuclear: Using uranium to create heat and electricity.
Benefit: Creates huge amounts of energy from a tiny amount of fuel. Drawback: Produces radioactive waste that is very hard to store safely.
2. Engineered Lifespans: How Long Should it Last?
Engineers have to decide at the start how long a product is meant to live. This is called the engineered lifespan.
• Planned Obsolescence: This is when a product is designed to become "out of date" or break after a certain time.
Example: A smartphone that slows down after three years so you buy the new model.
• Sealed Parts: Some products are "sealed for life." This means you can't open them to fix them.
Why do this? It can make the product waterproof or safer, but it means if one small part breaks, the whole thing might have to be thrown away.
• Maintenance Requirements: Some designs are built to last a long time, but only if the user looks after them.
Example: An airplane is designed to last decades, but only because it has very strict maintenance schedules.
3. Maintenance: Keeping it Running
Don't worry if "maintenance" sounds like a boring chore; in engineering, it’s a life-saver! We maintain products for two main reasons: Safety (making sure it doesn't hurt anyone) and Efficiency (making sure it doesn't waste energy).
Types of Maintenance Work:
• Lubrication: Adding oil or grease to moving parts to stop them grinding together. Analogy: Like putting oil on a squeaky bike chain.
• Avoiding Corrosion: Protecting metals from rusting using paint or special coatings.
• Compensating for Wear: Some parts are designed to wear down so the main machine doesn't. We have to replace these "wear parts" (like brake pads on a car).
• End of Life (EOL): Engineers must think about how to take the product apart and recycle the materials when it finally stops working.
Using Math to Predict the Future
Engineers use statistics to predict when a part will fail. If they know a lightbulb usually lasts 1,000 hours, they can tell a factory to change all their bulbs at 900 hours to avoid being left in the dark!
4. Availability and User Requirements
Sometimes your dream design is impossible because you can't get the materials, or they are too expensive.
Material Availability
If you use standard sizes (like the wood or metal pipes you can buy at a DIY store), your project will be cheap. If you need a "non-standard" size, it has to be specially made, which makes the cost skyrocket!
User Requirements
The person using the product (the "user") often has specific needs that change the design:
• High Strength / Low Weight: If a user wants a racing bike, it must be light but very strong. The engineer might choose Titanium or Carbon Fibre Composites.
The Catch: These materials are much harder to work with and require "specialist manufacturing processes," which makes the product more expensive.
Summary: The "Big Three" to Remember
1. Energy choice affects the environment and reliability.
2. Lifespans are a choice—you can design for a "quick fix" or "long-term" use.
3. Maintenance is essential for safety and making products last longer.
4. Material choice is a balance between what the user wants and what is available/affordable.