CHAPTER 2: ENGINEERING DISSECTION PROJECT
SKMJ 1902
ENGINEERING PRINCIPLES
AND PRACTICE
UTM JOHOR BAHRU
WHAT IS ENGINEERING DISSECTION?
Dismantling asks:
“How do I take this product apart?”�
Engineering dissection asks:
“Why is it built this way, and how does it work, and what physical principles govern its operation?”
Engineering dissection is not simply dismantling a product.
THE ENGINEERING DISSECTION METHOD
SEE → PREDICT → DISASSEMBLE → IDENTIFY → UNDERSTAND → FOLLOW THE PHYSICS → CONNECT THE MATHEMATICS
The objective is to move from simply seeing a complete product to understanding the systems, assemblies, components, functions, interactions, and physical principles inside it.
Engineering dissection is not simply dismantling a product.
STEP 1 — OBSERVE BEFORE TOUCHING
Before disassembling anything, observe the product as a black box.
What is this product?
What is its overall purpose?
What does it do?
What are the inputs?
What are the outputs?
What forms of energy enter and leave the system?
Example: Electric Fan
Electrical Energy + User Command → ELECTRIC FAN → Airflow + Motion + Heat + Sound
Key Principle: Understand the purpose of the system before examining its components.
STEP 2 — PREDICT WHAT IS INSIDE
Before opening the product, predict what you expect to find inside.
Ask:
“Based on the function of this product, what components do you expect to find inside?”
For example:
Motor? → Shaft? → Bearing? → Gear? → Switch? → Capacitor?
Make a simple sketch showing your predicted internal structure.
After disassembly, compare:
WHAT I EXPECTED → WHAT I ACTUALLY FOUND
STEP 3 — DISASSEMBLE SYSTEMATICALLY
Do not simply remove components.
For every disassembly step:
PHOTOGRAPH → LABEL → RECORD POSITION → RECORD CONNECTION → RECORD ORIENTATION → STORE SYSTEMATICALLY
Prepare a Disassembly Sequence Diagram.
Key Principle:
Do not just record what you removed. Record how the components were connected.
STEP 3 — DISASSEMBLE SYSTEMATICALLY
For example:
Complete Product�↓�Cover Removed�↓�Blade Removed�↓�Retaining Component Removed�↓�Motor Assembly Removed�↓�Motor Disassembled
STEP 4 — BUILD THE PRODUCT HIERARCHY
Do not view the product as a random collection of parts.
Organize it systematically:
PRODUCT → SYSTEM → ASSEMBLY → SUB-ASSEMBLY → COMPONENT
Example:
Electric Fan�↓�Drive System�↓�Motor Assembly�↓�Rotor/Shaft Assembly�↓�Shaft�↓�Bearing
STEP 5 — UNDERSTAND THE FUNCTION OF EACH COMPONENT
Do not stop after identifying the name of a component.
For every major component, ask:
WHAT IS IT?
What is the component called?
↓
WHAT DOES IT DO?
What is its function?
↓
HOW DOES IT WORK?
What mechanism allows it to perform its function?
↓
WHAT DOES IT INTERACT WITH?
Which other components are connected to it?
↓
WHAT HAPPENS IF IT IS REMOVED?
Can the system still function correctly?
Golden Rule: DON'T JUST NAME THE PART. EXPLAIN WHY THE PART EXISTS.
STEP 5 — UNDERSTAND THE FUNCTION OF EACH COMPONENT
EXAMPLE — BEARING
What is it?
A bearing.
What does it do?
It supports a rotating shaft and allows relative motion with low friction.
How does it work?
Rolling elements separate the rotating and stationary components while transmitting loads.
STEP 5 — UNDERSTAND THE FUNCTION OF EACH COMPONENT
EXAMPLE — BEARING
What does it interact with?
The shaft and housing.
What happens if it is removed?
The shaft may not be properly supported, resulting in excessive friction, vibration, misalignment, wear, or failure.
This is the difference between:
“I know what this component is.”
and
“I understand why this component is required.”
STEP 6 — FOLLOW THE PHYSICS
Once you understand the components and their functions, ask:
“What physical phenomena are happening inside this machine?”
Look for:
FORCE • MOTION • ENERGY • HEAT • FLUID FLOW • FRICTION • DEFORMATION • VIBRATION
For every major component, identify the relevant physical phenomena.
STEP 6 — FOLLOW THE PHYSICS
Example: Drone Propeller
Motor rotates the propeller�↓�Propeller accelerates air�↓�Air is pushed downward�↓�Aerodynamic force is generated�↓�Thrust acts on the drone
Then ask:
“What physical principles would an engineer need to understand to explain this behavior?”
Force & Equilibrium → Statics
Motion & Acceleration → Dynamics
Stress & Deformation → Solid Mechanics
Air/Water Flow → Fluid Mechanics
Heat & Energy → Thermodynamics / Heat Transfer
Rotation & Power Transmission → Machine/Component Design
Sensors & Actuators → Mechatronics
Feedback & Stability → Control Engineering
STEP 7 — CONNECT THE PHYSICS TO MATHEMATICS
Example: Drone Propeller
Motor rotates the propeller�↓�Propeller accelerates air�↓�Air is pushed downward�↓�Aerodynamic force is generated�↓�Thrust acts on the drone
Then ask:
“What physical principles would an engineer need to understand to explain this behavior?”
STEP 7 — CONNECT THE PHYSICS TO MATHEMATICS
At this stage, you are NOT expected to perform advanced engineering calculations.
Question:
“If an engineer wanted to analyze this system quantitatively, what would need to be calculated?”
STEP 7 — CONNECT THE PHYSICS TO MATHEMATICS
Example: Shaft
Physical quantities:
Force • Torque • Rotational Speed • Power • Deformation
Possible mathematical tools:
Algebra • Geometry • Trigonometry • Vectors • Calculus • Differential Equations
You are not yet expected to perform all these analyses.
Your objective is to recognize:
WHAT needs to be calculated and WHAT mathematics may eventually be required to calculate it.
THE COMPLETE DISSECTION THINKING PROCESS
1. SEE IT
What is this machine supposed to do?
↓
2. PREDICT IT
What do I expect to find inside?
↓
3. OPEN IT
How is it assembled?
↓
4. IDENTIFY IT
What are the systems, assemblies, and components?
↓
5. QUESTION IT
Why is each component there?
↓
6. UNDERSTAND IT
How do the components interact?
↓
7. FOLLOW THE PHYSICS
Where are the forces, motion, energy, heat, fluid flow, friction, and deformation?
↓
8. CONNECT THE MATHEMATICS
What would an engineer need to calculate?
THE MOST IMPORTANT QUESTION
For every component you discover, repeatedly ask:
WHY IS THIS COMPONENT HERE?
Then:
What does it do?�How does it work?�What does it interact with?�What physics governs it?�What would happen without it?�What would an engineer need to calculate to analyse it?
REASSEMBLY IS PART OF DISSECTION
Students should:
DISASSEMBLE → UNDERSTAND → REASSEMBLE → VERIFY
Where appropriate and safe, the product should function again after reassembly.
Why?
Successful reassembly demonstrates understanding of:
Component position • Orientation • Interfaces • Connections • Assembly sequence • Component relationships
WHAT SHOULD YOU SEE AFTER DISSECTION?
Before dissection, you may see:
“This is a machine.”
After dissection, you should see:
SYSTEM → ASSEMBLIES → COMPONENTS → FUNCTIONS → INTERACTIONS → PHYSICAL PHENOMENA → PHYSICAL PRINCIPLES → MATHEMATICS
The objective is to change how you see engineering products.
PHILOSOPHY
A beginner sees a machine.
�An engineering student sees components.
�An engineer sees functions, interactions, forces, motion, energy, and physical principles.
Therefore:
SEE THE MACHINE → UNDERSTAND THE COMPONENTS → UNDERSTAND HOW THEY WORK → IDENTIFY THE PHYSICS → IDENTIFY THE MATHEMATICS
PHILOSOPHY
And this provides an excellent bridge to the next project:
PROJECT 1: DISSECTION
Existing Machine → Understand It
↓
PROJECT 2: DESIGN
Engineering Problem → Create a Solution
The first project teaches students to understand how existing machines work. The second teaches them to use that understanding to create new engineering solutions.