Garage door

remote opener

MMAE 445 COMPUTER-AIDED DESIGN

GERARD SIMON PROSPER

A20346049

Data that is given in Handout

1. 5% standard deviation all dimension

2. 99.9% fit in the opener

3. 99.9% operation

4. Length between sensors = 10mm

5. Length of the opener (including push) = 40mm

6. Height of Sensor Box = 10mm

Properties of Spring

Music wire

K = 0.3 N/mm

Squared and Ground

d = 0.95mm

G = 81.7 GPa (Table 10-5)

Ls = 20mm

Lfree = 38mm

Nt = 15turns (Table 10-1)

D = 10.12mm (Equation 10-9)

Music wire description &

Information

Battery Used

Dimensions :

Type

1/2 AAA

Diameter (mm)

10.5

Height (mm)

22

Part 1:Garage door opener

#1 Ensure the spring will always fit in the opener,

99.9% of the time.

Conditions :

I. Diameter of Opener should be bigger than the diameter of spring.

II. The diameter of spring should be smaller than 15mm

Satisfying condition 1 – the

diameter of the button was chosen

to be 12.5mm

Satisfying condition 2 – diameter

does not cross 15mm

#2 Ensure the button will always be protruding out of

the door opener with enough length to cause a

nominal 3N force to activate the sensor.

The length of the button from the top to the bottom of the

outer part of the sensor was to be 10mm. In order to ensure that

the sensor will be activated, the length of the button was

increased to 13mm for better accuracy.

#3 Find out the length of a typical battery (AA or AAA,

depending on what you prefer to use) and size up the sensor

box, so that your sensors from the button and the sensor box

will be aligned 99.9% of the time when the button is depressed

with a maximum force of 3N.

For this condition to be satisfied, the length the button

has to travel is 10mm for the sensor to work. To ensure

that it will be aligned 99.9% of the time, stochastic

analysis was done to find the minimum length that it

need to travel to achieve this success rate.

Calculations are as follows :

Calculations for part 3

Distance between sensor in remote

Sensor

Sensor

4.14mm

#4 Think about a minimum force that your device will require

to active the door opener. It cannot be too low, or it is too

sensitive. Make sure your design is not such that the opener is

activated too easily.

For an operation of 99.9%, the length of sensors should be

4.14mm. Hence, the minimum displacement that the spring

needs to travel is 5.86mm ( 10 – 4.14 ).

From equation F =K*x

Fmin = 0.3 * 0.586 = 0.1758N

Solidworks parts and assembly

Part 2: Using a standard deviation

of 0.5% instead of 5% for question 1

BASED ON THE CALCULATIONS DONE, THE DIAMETER NEEDS TO BE BIGGER THAN 10.15MM AND THE CURRENT DESIGN DIAMETER IS 12.5MM WHICH IS STILL ACCEPTABLE

Using a standard deviation of 0.5%

instead of 5% for question 2

BASED ON THE CALCULATIONS DONE, THE LENGTH BETWEEN THE SENSORS NEEDS TO BE 0.69597MM IN ORDER FOR THE SENSORS TO WORK 99.9% OF THE TIME.

Summary for change in standard

deviation

For the length between the two sensors, a change in

standard deviation results in a much lower range for

the sensors to work at a rate of 99.9%. For a standard

deviation of 5%, the length was 4.14mm while for a

standard deviation of 0.5%, the length drastically

reduced to 0.69mm which is a reduction in 83.3%.

Part 3: garage door opener analysis

using abaqus cae

Material chosen and properties

Aluminum 6061

- Young Modulus : 68.9 GPA

- Poisson's Ratio : 0.33

- Yield Strength : 276 MPA

- UTS : 310 MPA

1st part : Button (original design)

ORIGINAL DESIGN TET MESH WITH

NODES

LOAD OF 10N

APPLIED

1st part : Button (original design)

A MAX

DISPLACEMENT OF

1.675e-08.

Von Miser Stress

Design changes made to 1st button

The fillet of the button was reduced from 0.10 inches to 0.05 inches.

This would reduce the stress concentrations on a smaller portion of

the button and distribute the stress more evenly.

1st part : Button (new design)

TET MESH Load and Boundary conditions being applied

1st part : Button (NEW design)

A reduced max displacement

from1.675e-08 to 7.634e-09 Von Miser Stress (Reduced from 5.36e04 to

6.925e03 )

2nd part : holder (original design)

TET MESH WITH

NODES

Load of 45 Newton's applied and

boundary conditions

2nd part : holder(original design)

A MAX

DISPLACEMENT OF

3.3e-06.

Von Miser Stress

Design changes made to 2nd

holder

The thickness of the holder was increased from 0.5 in to 0.75 inches

This would reduce the stress concentrations greatly on the

concentrated areas of stress.

2nd part : holder(new design)

A reduced displacement from 3.3e-06 to

2.93e-6 (Load was still maintained at 45

Newton's).

Von Miser Stress (Reduced from 2.882e03 to

2.562e03)

Summary for change of parts

design

When either design was changed, a reduction in maximum

displacement that will happen with a lower Von Miser stress.

Other methods to reduce stresses besides design changes would be to change the material used.

For this analysis, Aluminum 6061 was used. If Aluminum 7075 was

used as an example, the Young’s Modulus will increase from

68.9GPa to 71.7GPa. Other mechanical properties such as UTS will

also increase. This increase in properties will allow for the material to

be stronger hence, it will deform less under constant loading.

Part 4 : Heat transfer analysis on

holder (BOX)

Thermal properties of Aluminum 7075

Thermal Conductivity :130 W/m-K

Specific Heat Capacity : 0.96 J/g-°C

Outside BC : 30 Celcius

Inside BC : 45 Celcius

Maximum Temperature : 100 Celcius

Concentrated Heat Flux : 0.5 Watts/m^2

Nodes showing where the battery would transfer heat to the box when in operation.

Yellow nodes at the edges show the Boundary Condition and the white nodes shows the concentrated heat flux that was applied.

Heat Flux Magnitude showing temperature distribution.

The inside has a temperature boundary of 45 Celsius but the maximum temperature that is experienced is 47.47 Celsius. From this high temperature, a reduction can be seen until 30 Celsius as this was the boundary at the outer box. A temperature distribution of 47 Celsius to 30 Celsius can be observed for this box.