156B Week 5

Overview of Status of Analysis, Design, Fabrication, Tests, etc.

• • Reworking our design because the original design did not meet the 10Hz 1st mode requirement in FEMAP.

  • Resolved some errors and confusions in FEMAP Model by sponsor

  • The material specifications have been decided for the legs

Accomplishments from Previous Week

• • Received the order of prototype locking collar and hinge from McMaster Carr.

  • Reworking model of the stand to make it more structurally stable.

Goals for Next Week (list names after each item). Use specific and measurable objectives.

• • Rework design of stand and perform FEMAP analysis (David) 

  • Test the legs with the new collar from Mcmaster (Steven)

  • Test torque rating of hinges to make sure they are strong enough (Alex)

  • Place an order for the final materials for the aluminum tubing (Alex)

  • Place an order for all the clamps of each size (Alex)

  • Find and contact a grinding shop to discuss prices and options for machining the legs (Kwan)

  • Test locktite and JB weld (Kwan)

  • Assign Roles for the report(Team)

  • Initial designs for rungs and base ratchet strap structure. (Team)

  • Purchase ratchet straps from home depot (Kwan)

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)

• • Concerned that the lever lock hinges may not be adequate enough to support the bending moment of the legs.

  • Favor clamps to hold the rungs rather than welding or press fitting with locktite.

  • Lean toward off the shelf parts to avoid any custom made parts in the future.

Instructor Comments from Last Meeting and Actions Taken to Address these Comments  (indicate date of comments and if via email or in person)

• • Suggested using stainless steel tube on top

  • Spring load pin

Comments from Other Students in the Class (indicate date of comments and if via email or in person)

• • Fabrication advice for clamp (4/22)

Risks and Areas of Concern

• • Femap Model showed the original design did not meet the 10Hz 1st mode requirement in FEMAP.

  • Lubricant added to the legs will reduce the friction coefficient increasing the likelihood that the legs will slip when clamped

  • Machining each leg ourselves will take a large amount of time and this will decrease the possibility that our sponsor will reproduce our product in the future

  • The tubing that is order and received will not have all have the same inner and outer diameters creating inconsistent machining instructions for the grind shop

Resources or Information Required but not Available

Schedule

• • 4/29/13 - Presentation

  • 5/2/13 - Testing collar and hinges

  • 4/29/13-5/1/13 - Redesign structure and outline Rungs

  • 5/1/13-5/3/2013 - Femap analysis

  • 5/3/13 - Meet with the sponsor

  • 5/5/13 - Purchase Ratchet Straps and Ratchet Mechanism

Budget (list amount spent and amount remaining)

• • Spent: $170

    • $130 (Tubing Prototypes)

    • $40 (Collar and hinge) 

  • Remaining: $1330

Progress on Report and Webpage

• • Preliminary draft of the report is still in progress