Before and After
Façade of a Building
Design a mounting solution for an awning covering a window in a home.
Understand the problem
What is an awning ?
An awning or overhang is a covering attached to the exterior wall of a building to provide shelter from the elements like Rain , sunshine.
Analyse to understand the problem in the best way possible
Understand the design of a generic awning there are certain elements to the design
Extract the Input
How to extract Input ?
Reverse engineering – Measurements
Taking physical measurements of the problem space
Form of Input Data
Measurements should be converted into a CAD model
An assembly mechanism
To maintain the look of the façade of the building and not look out of place..
Now that the requirements are understood.
Next step is to generate concepts.
How to Generate Concepts ?
Awning – Concept
Concept of mounting 1
Awning is connected to the Wall by a Link with pin joints at either end
Link is Aluminium channel
Concept of mounting 2
Awning is connected to the Wall rigidly through the Red frame on either side of Awning
Bracket is Wooden
Comparison of Concepts
|Concept 1||Concept 2|
|Uses a link to connect the Awning to the wall||Uses a structural bracket which connects the awning to the wall|
|Uses Pin joints – temporary||Uses Permanent joints|
|Easier to dismantle||Cannot be dismantled|
|Additional brackets for mounting pins||No additional brackets for pin mountings|
|Inferior in Aesthetics||Superior in Aesthetics|
|Can take lesser loads||Can take larger loads|
Selecting a concept and the reasoning behind it ?
Although in this case Concept 1 has been considered superior but this might not be the case in all other instances of design
Analysis of the Design with respect to Engineering principles
1. Engineering mechanics
2. Strength of materials
3. Machine design
Converting the design problem to an Engineering problem
Formulating the engineering problem
Arriving at the Design load
Wind Load direction
Wind pressure calculations
150 km / h =42 m / s
Generic formula for wind pressure , P = 0.613 V^2
Source : Wikihow
Considering the area of application faces a year round probability of storms then the maximum velocity of wind
For a sever storm is maximum 150 km/h
Calculated Pressure (N/m^2) –
= 0.613 * 42^2
= 1081 N/m^2
Calculate the Load from pressure
Projected area of the Awning is 1 metre X 0.7 metre = 0.7 m^2
Load acting = Pressure X Area
Load = 1081 * 0.7 = 756.7 N or 76 kg
Self Weight calculation
Self weight , Sheet = 11 kg
Frame = 10 kg
Total Design load = Wind load + Self weight load
= 76 +11+10 = 100 kg
Assumed : Although the Weight will act vertically downwards, the Load due to self weight is a fraction of the wind load.
Considering Overload factor as 1.5
Cause of Overloads?
Load to be considered = 150 kg = 1500 N
Static Force and Moment analysis
Free body diagram for system
Load acting is 1500/ 2 (at one side) at centre of the link.
Free body diagram
Kinematically it is a structure – Triangle
Free body diagram – Using Method of sections
Resolving the load into vertical and horizontal components
Using Triangle Law
Θ = 12.7 degree
sinθ = H/750
H = (sin 12.7)*750
H = (0.219)*750
cosθ = V/750
V = (cos 12.7)*750
V = (0.9755)*750
Resolving the Fce force into vertical and horizontal components
sinθ = H/Fce
H = (sin 59)*Fce
H = (0.857)*Fce
cosθ = V/Fce
V = (cos 59)*Fce
V = (0.515)*Fce
Free Body Diagram