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 Watch • Chosen Movement Method and Movement Assist • Calculations • ANSYS Models • Selected Lazy Suzan • Risk Analysis • Project Schedule • Chair Benchmarks • Questions 2

P14031 Problem Statement Current State • A jib transfer bench was created in Spring 2013 (P13031) that is heavy, o expensive, labor-intensive to assemble, and accommodating of a strict size constraint present at the time. Desired State • A jib transfer bench that enables a jib trimmer to move transversely across the o width of the sailboat, without the use of their legs or core muscles. Project Goals • A fully-functional prototype that is: o lighter • cheaper • easier to assemble and manufacture • Constraints • Designed for use with the Sonar class of sailboats o Completely mechanical solution o Designed for ease of reproducibility o Cannot require alteration of the boat or cause damage o 3 1-page Project Summary (EDGE)

Critical Subsystems • Movement method • Why? Linear vs. rotational Most technically challenging o o design elements Directly effect many of the o • Movement assist most important customer and engineering requirements Gravity? o Assist bar? o Pulley or other systems? o 4

Design to Pursue (10/3) • Customer likes: Moves side to side o Didn’t look intimidating o • Customer dislikes: Doesn’t span over benches o Binding potential o More moving parts o 5

Design to Pursue (10/15) • Advantages: Simplicity o Goes out over benches o • Disadvantages: Moment is HUUUUUGGGE, o Rochester, HUUUUUUUGGE!!!! 6

Customer Requirements 7 Importance Scale: 1 = High Priority, 2 = Medium Priority, 3 = Low Priority

Engineering Requirements 8 Updated HOQ on EDGE

Key Constraints to Watch • Simple design! We received feedback from Caitlyn at Piers Park that all previous o iterations were WAY over-engineered • Easy installation • Use with a wide range of users Chair design/dimensions o Movement assist devices o • An un-intimidating design • Do not limit feeling of freedom by securing user too much • Budget decreased from $2,500 to $1,000 9

Movement Method Chosen • Rotational Lazy Susan design • Similar to Team Paradise design (Paralympic Sport Club out of Miami, FL) http://www.teamparadise.org/adaptive_equipment 10

Calculations – Movement Method Overall Assumptions: Base Tear-Out (Worst Case Load) Load at end of arm = 350 lbs Arm radius = 22" Load Arm height = 14" Required to Minimum Plywood Number of Washer Tear the Turntable Thickness Bolts Diameter (in) Turntable Out Bolt-Circle (in) of the Base Diameter (in) Assumptions: (Lbs) Note: Worst case load is a heel 4 0.75 1 1178 13.57 angle of 45 deg, the user starts 8 0.5 0.75 1377 13.74 Plywood is an Isotropic material at the higher side and swings 8 0.75 0.75 2062 9.43 unimpeded to the lower side. Load is Evenly Distributed Over all Bolts Safety Factor of 1.5 Boat Deck Tear-Out (Worst Case Load) Materials are Rigid Part 1: Hand Calculations Load on Load on Assumptions (Hand Calcs): Assumptions (ANSYS): Deck from Pressure on Pressure on Clamps (A1) Balsa and CSM are Isotropic Base (A2) A1 (Psi) A2 (Psi) Load is Applied Evenly Over Entire Area (Lbs) Materials (Lbs) Materials are Rigid There are 4 Layers of Roving 714 962 155 2.7 Pressure Constant Over Area Static Analysis Gravity is Ignored Bearing Requirements (Worst Case Load) Pressure Constant Over Area Minimum Roving Layers 0.030" thick Dynamic Turntable Lower Load Higher Load Load Assumptions: CSM 0.045" thick Diameter (in) (Lbs) (Lbs) Capacity Safety Factor of 1.5 CSM Poisson's ratio is 0.3 (Lbs) 12 370 1842 517 Ball Bearings 16 370 1412 398 18 370 1269 359 Desired Life of 13000 Cycles 11 Cyclic Loading Standard Rated Life of 10 6 Cycles

Selected Lazy Susan • Lazy Susan: $15.46 Need an 8-hole pattern o 1000 lbs capacity o 5/16” thick o 12” outside diameter o 2 lb weight o VXB Part # Kit8999 o • Marine-grade plywood to mount upon ¾” thick o http://www.amazon.com/Capacity-Bearing-Turntable-Bearings-VXB/dp/B0045DV04I 12

Movement Assist • Gravity! • Stability bar • Lock-in position on each side? • Braking method? 13

Calculations – Movement Assist • Max transfer speed Assumptions: • Moment on lazy Susan 22" (1.83ft) radius • Will fiberglass floor be Frictionless damaged? Conc. of energy Transfer Speed Speed at ending Speed at ending Centripetal Heel angle (deg) Starting Position Ending Position acceleration (ft/sec 2 ) position (mph) position (ft/s) 45 Side Other side 4.00 5.875 18.56 45 Side Middle 3.45 5.054 13.96 14

Positions of Loads 15

ANSYS – BC and Applied Loads 16

ANSYS – Material Layers 17

ANSYS - Deflection 18

ANSYS – Stress Analysis 19

Risk Analysis Risk Severity Probability Hazard Actions to reduce failure Risk Cause (why it happens) Effects Number Score mode User impacts bulkhead Inadequate/dysfunctional Extensive testing of braking 1 User uncomfortably jostled 2 2 4 during transfer braking mechanism mechanism Keep customer informed Customer does not like throughout the design Mis-interpreted customer Device is not used by the 2 some parts of the 2 1 2 process, seeking feedback requirements customer design and checking design with customer Break edges of all 3 System damages boat Device has sharp corners Unhappy boat owner 2 1 2 components Double check stress System damages boat 4 Unreliable stress analysis Potential injury 3 1 3 analysis & increase factor of floor safety Design robust vertical 5 Seat scuffs bench Unwanted seat deflection Seat hits top of bench 1 3 3 support(s) Team becomes Incomplete/unreasonable Discuss issues with 6 Incompatible personalities 3 1 3 unproductive project group/advisor Use cover when in Environmental 7 Weather Device no longer useable 1 3 3 storage/use appropriate Deterioration materials Properly model boat’s inside Unsafe for user to use Improperly constrained 3 1 3 Improperly secured in (device may fall out) dimensions 8 boat Poor install Unsafe for user to use 2 2 4 Clear install instructions Installation team becomes Overdesigned components frustrated/injured Select light materials 9 Device is overweight Unreasonable 1 2 2 Keep weight in mind while expectations Unable to use in races designing Device does not User is uncomfortable and Person does not fit in Ensure device is 10 accomodate wide enough may choose to not use the 1 2 2 device comfortably ergonomically designed range of body types device 20

Risk Analysis - Continued Risk Severity Probability Hazard Risk Cause (why it happens) Effects Actions to reduce failure mode Number Score Improper initial sonar Unusable device 2 1 2 Measure twice Device does not fit in measurments 11 boat Improper tolerancing Unusable device 2 1 2 Measure several boats Cannot access jib 12 Poor design Unusable device 3 1 3 Design with anthropometric data lines Boom impacts user's Maximize the possible distance 13 Seat is too high Potential injury 2 2 4 head between boom and seat User has poor 14 Large vertical footprint Unsafe for user 2 1 2 Small vertical profile visibility Distance between bench and device seat is more than 200mm Keep regulations in mind while Does not comply Device is permanently Device cannot designing the system (Mechanical 15 with ISAF/IFDS 2 2 4 fastened or requires be used in races solution, Non-permanent install, No regulations modification of the boat modifications) Device does contains non- mechanical component Decreased Lots of manufacturing time 1 1 1 Minimize the number of parts Complicated Reproducibility 16 construction Lots of custom parts High cost 1 2 2 COTS parts Unhappy Lots of components 2 1 2 Minimize subsystem breakdown installers Complicated to 17 install Unhappy Poor instructions 1 1 1 Clear install instructions installers ANSYS model Incomplete published data for 18 Boat deck failure 3 2 6 Obtain boat floor sample to test inaccurate material properties 21