P14031: Jib Transfer Bench Matt Brunelle Nicole Conway Mike - - PowerPoint PPT Presentation
Sub-System Design P14031: Jib Transfer Bench Matt Brunelle Nicole Conway Mike Kennedy Katy Wurman 1 Agenda Critical Subsystems Design to Pursue (old and new) Customer and Engineering Requirements (updated) Key Constraints to
Matt Brunelle Nicole Conway Mike Kennedy Katy Wurman
Sub-System Design
1
2
expensive, labor-intensive to assemble, and accommodating of a strict size constraint present at the time.
width of the sailboat, without the use of their legs or core muscles.
3
1-page Project Summary (EDGE)
design elements
most important customer and engineering requirements
4
5
6
Rochester, HUUUUUUUGGE!!!!
Importance Scale: 1 = High Priority, 2 = Medium Priority, 3 = Low Priority
7
Engineering Requirements
8
Updated HOQ on EDGE
iterations were WAY over-engineered
much
9
design
Paradise design (Paralympic Sport Club
10
http://www.teamparadise.org/adaptive_equipment
11
Base Tear-Out (Worst Case Load) Number of Bolts Plywood Thickness (in) Washer Diameter (in) Load Required to Tear the Turntable Out
(Lbs) Minimum Turntable Bolt-Circle Diameter (in) 4 0.75 1 1178 13.57 8 0.5 0.75 1377 13.74 8 0.75 0.75 2062 9.43 Boat Deck Tear-Out (Worst Case Load) Part 1: Hand Calculations Load on Clamps (A1) (Lbs) Load on Deck from Base (A2) (Lbs) Pressure on A1 (Psi) Pressure on A2 (Psi) 714 962 155 2.7 Bearing Requirements (Worst Case Load) Turntable Diameter (in) Lower Load (Lbs) Higher Load (Lbs) Minimum Dynamic Load Capacity (Lbs) 12 370 1842 517 16 370 1412 398 18 370 1269 359 Overall Assumptions: Load at end of arm = 350 lbs Arm radius = 22" Arm height = 14" Assumptions: Note: Worst case load is a heel angle of 45 deg, the user starts at the higher side and swings unimpeded to the lower side. Plywood is an Isotropic material Load is Evenly Distributed Over all Bolts Safety Factor of 1.5 Materials are Rigid Assumptions (Hand Calcs): Assumptions (ANSYS): Load is Applied Evenly Over Entire Area Balsa and CSM are Isotropic Materials Materials are Rigid There are 4 Layers of Roving Pressure Constant Over Area Static Analysis Gravity is Ignored Pressure Constant Over Area Roving Layers 0.030" thick Assumptions: CSM 0.045" thick Safety Factor of 1.5 CSM Poisson's ratio is 0.3 Ball Bearings Desired Life of 13000 Cycles Cyclic Loading Standard Rated Life of 106 Cycles
12
to mount upon
http://www.amazon.com/Capacity-Bearing-Turntable-Bearings-VXB/dp/B0045DV04I
each side?
13
14
Transfer Speed Heel angle (deg) Starting Position Ending Position Speed at ending position (mph) Speed at ending position (ft/s) Centripetal acceleration (ft/sec2) 45 Side Other side 4.00 5.875 18.56 45 Side Middle 3.45 5.054 13.96
damaged?
Assumptions: 22" (1.83ft) radius Frictionless
15
16
17
18
19
Risk Number Risk Cause (why it happens) Effects Severity Probability Hazard Score Actions to reduce failure mode 1 User impacts bulkhead during transfer Inadequate/dysfunctional braking mechanism User uncomfortably jostled 2 2 4 Extensive testing of braking mechanism 2 Customer does not like some parts of the design Mis-interpreted customer requirements Device is not used by the customer 2 1 2 Keep customer informed throughout the design process, seeking feedback and checking design with customer 3 System damages boat Device has sharp corners Unhappy boat owner 2 1 2 Break edges of all components 4 System damages boat floor Unreliable stress analysis Potential injury 3 1 3 Double check stress analysis & increase factor of safety 5 Seat scuffs bench Unwanted seat deflection Seat hits top of bench 1 3 3 Design robust vertical support(s) 6 Team becomes unproductive Incompatible personalities Incomplete/unreasonable project 3 1 3 Discuss issues with group/advisor 7 Environmental Deterioration Weather Device no longer useable 1 3 3 Use cover when in storage/use appropriate materials 8 Improperly secured in boat Improperly constrained Unsafe for user to use (device may fall out) 3 1 3 Properly model boat’s inside dimensions Poor install Unsafe for user to use 2 2 4 Clear install instructions 9 Device is overweight Overdesigned components Unreasonable expectations Installation team becomes frustrated/injured Unable to use in races 1 2 2 Select light materials Keep weight in mind while designing 10 Person does not fit in device comfortably Device does not accomodate wide enough range of body types User is uncomfortable and may choose to not use the device 1 2 2 Ensure device is ergonomically designed
20
Risk Number Risk Cause (why it happens) Effects Severity Probability Hazard Score Actions to reduce failure mode 11 Device does not fit in boat Improper initial sonar measurments Unusable device 2 1 2 Measure twice Improper tolerancing Unusable device 2 1 2 Measure several boats 12 Cannot access jib lines Poor design Unusable device 3 1 3 Design with anthropometric data 13 Boom impacts user's head Seat is too high Potential injury 2 2 4 Maximize the possible distance between boom and seat 14 User has poor visibility Large vertical footprint Unsafe for user 2 1 2 Small vertical profile 15 Does not comply with ISAF/IFDS regulations Distance between bench and device seat is more than 200mm Device cannot be used in races 2 2 4 Keep regulations in mind while designing the system (Mechanical solution, Non-permanent install, No modifications) Device is permanently fastened or requires modification of the boat Device does contains non- mechanical component 16 Complicated construction Lots of manufacturing time Decreased Reproducibility 1 1 1 Minimize the number of parts Lots of custom parts High cost 1 2 2 COTS parts 17 Complicated to install Lots of components Unhappy installers 2 1 2 Minimize subsystem breakdown Poor instructions Unhappy installers 1 1 1 Clear install instructions 18 ANSYS model inaccurate Incomplete published data for material properties Boat deck failure 3 2 6 Obtain boat floor sample to test
21
22
Task Description Planned Start Planned End Planned Duration Actual Start Actual End Actual Duration Longer than planned? If yes, why? Design of Rotational Movement Mechanism 10/4/2013 10/4/2013 1 10/16/2013 10/23/2013 7 YES With the changed design the Rotational movement mechanism became a more important subsystem and needed more focus. Also, calculations done twice (static & dynamic loads) Design of Lateral Movement Mechanism 10/4/2013 10/11/2013 7 N/A N/A N/A N/A N/A Device Interface with Sonar 10/9/2013 10/17/2013 8 10/16/2013 10/27/2013 11 YES The interface is more complicated and a more critical part of the design with the switch to the cantilevered seat design Design of Movement Assist Mechanism 10/14/2013 10/17/2013 3 10/16/2013 10/21/2013 5 YES Scheduling conflits with team members Risk Analysis (Update) 10/18/2013 10/21/2013 3 10/24/2013 10/25/2013 2 NO Detailed Test Plan for high risk subsystem 10/18/2013 10/21/2013 3 10/28/2013 10/28/13 1 NO Subsystem Design Phase Presentation & Peer Reviews 10/24/2013 10/24/2013 1 10/29/2013 10/29/2013 1 NO
23
24
25
http://www.designflick.com/2012/06/cantilever-chair-by-choi-byung- hoon.html -priceless http://www.contextgallery.com/shop/panton- cantilever-chair-standard/ -$255 http://www.ssbtractor.com/page40.html -$143
http://www.ssbtractor.com/page40.html -$80.29
26
http://photo.americascup.com/25-09-2013-San-Francisco-USA-CA-34th-America-s-Cup-,en,igf1724p96n53.html t/ls2-sonar.html#previous-photo
t/ls2-sonar.html#previous-photo
t/sonar2.html#previous-photo
27
Cantilevered Arm Curved Track Linear Track over Bench
Floor Track
28
Design 1 Linear track above the benches Design 2 Linear track on the floor between benches Design 3 Curved track above benches Design 4 Cantilevered arm Design 5 Coaster (negative x-squared) Design 6 Original (Current Design)
Criteria Design 1 Design 2 Design 3 Design 4 Design 5 Design 6 Access to jib lines
+ DATUM Estimated material cost + +
+
+
+ +
Footprint +
Linear range of movement
+
+ COTS Components + + Ease of construction +
3 8 1 6 1
Sum -
2 7 3 4
Sum 0
8 1 3 2 6
Total
3 6
3
29
Design 1 Linear track above the benches Design 2 Linear track on the floor between benches Design 3 Curved track above benches Design 4 Cantilevered arm Design 5 Coaster (negative x-squared) Design 6 Original (Current Design)
Criteria Design 1 Design 2 Design 3 Design 4 Design 5 Design 6 Access to jib lines + DATUM + +
Estimated material cost
+ + + + + Transfer time
2 2 6 1 2 Sum - 5 9 5 8 7 Sum 0 4 2 2 Total
1
30
31
Design 2 – Ratchet and Lever Design 1 – Block & Tackle w/ Tensioner and Cleats Design 3 – Stability Bar w/ Carabiners Design 4 – Hand Cranks (double boat winch) Design 6 – Block & Tackle w/ Tensioner and Carabiners Design 5 – Center-Mounted Crank
Criteria Design 1 Design 2 Design 3 Design 4 Design 5 Design 6 Original Possibility of pinch points + + + + DATUM Time to transfer between sides
Effort to transfer between sides +
Estimated cost
+
2 1 3 2 2 1 Sum - 1 4 1 2 3 1 Sum 0 3 1 2 2 1 4 Total 1
2
Criteria Design 1 Design 2 Design 3 Design 4 Design 5 Design 6 Original Possibility of pinch points
sides
sides +
+ + + Estimated cost +
+ COTS components +
+ + Feasibility of design
3 2 1 3 3 Sum - 3 6 3 3 3 3 Sum 0 1 2 Total
*** assume that the user does not have a stability bar***
Movement mechanism Locking Position Design 1 Block and tackle with tensioner Cleats Design 2 Ratchet and lever None (self locking) Design 3 Stability bar Carabiners Design 4 Hand crank (double boat winch) None (self locking) Design 5 Center mounted crank Carabiners from chair Design 6 Block and tackle with tensioner Carabiners
32
OR
method?
33