156B Week 4

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

• New possible component - piezo ring for measuring force on o-ring

• Prototype is imminent

• First Proof of Concept test is imminent

Accomplishments from Previous Week

• Acquired access to an Instron for measuring spring properties of o-rings (Thanks Steve Roberts!)

• Re-configured Instron machine and software (Russ)

• Reviewed safety measures for piezo operation and handling (Kyle)

• Researched and purchased varying o ring materials (Jenessa)

• Further developed a DUT layer design (Chris)

• Purchased pogo pins (Chris)

• Found and purchased 2 piezo actuators! (Jenessa and Chris)

• Design of a preloading mechanism for piezo and oring (Kyle and Russ)

• Preliminary calculations for piezo operation constraints (Kyle)

• Started Proof of Concept Presentation (Kyle)

• Design of a plunger/casing for piezo (Kyle)

• 3D printed prototype for preloading mechanism and plunger/casing (Kyle)

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

• Learn software of new amp - Jenessa

• Develop LabVIEW testing software - Russ

• Develop and solve vibrations model for system - Jenessa

• Build preloading mechanism prototype - Kyle

• Machine DUT plates - Chris

• Build DUT plate assembly - Chris

• Create safety checklist for system operation - Kyle

• Develop a pseudo operations manual - All

• Testing - All

• Website Development - Russ

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

• We need to make two different port plates for testing front and back sides of MEMS (Sponsor, weekly meeting)

  • First plate has direct port, second plate has jogged port to simulate routing to back of MEMS

• Should have a feature to lock down setup (Sponsor, weekly meeting)

  • We hope that the large mass in the preload system will stabilize the system

• Look into a mounting face on piezo - ask manufacturer best way to mount (Sponsor, weekly meeting)

  • Can specify custom constraints to supplier for final design piezo actuator.

• Tester stack ; get testing as soon as possible to make up for long lead time of other piezo stack (Sponsor, weekly meeting)

  • bought 2, designed casing for it since it was just the piezo stack alone

• Find a way to make data-results display in real time when testing (Sponsor, weekly meeting)

  • • Working on it

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

• Consider making a spring-mass dynamic model of assembly to aid in best way of mounting the stack and compressing o-rings (Dr Tustaniwsky, weekly meeting)

  • Met again with professor to clarify model constraints

    • Working on defining model parameters (spring constants)

• Use Instron to test o-rings (Collective thought)

  • See accomplishments

• Use spring to measure preload on piezo (Dr Tustaniwsky, weekly meeting)

  • Making prototype

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

• • We need to work on our presentation style and delivery.

  • Mumbling during presentation

  • Minimize text on slides

  • Goniometer stage for positioning

Risks and Areas of Concern

• Resonant frequency - literature on piezo site says resonant frequency is greatly reduced when stack is unilaterally fixed, and when extra mass is attached.

  • Need to minimize mass of plunger without sacrificing stiffness

• High frequency noise at mated surfaces

  • Considering damper rings at all mechanical fittings

• Flexibility of plunger causing distortion

  • It is possible that this wont be an issue if the distortion is minor and radial, since the pressure waves will be going through the ports anyways

  • Is there an entrance effect there?

• Resist force of o ring seal compression causing plunger to flex.

  • What about a thin gasket instead? Would remove the o ring compression load requirement

• flexibility of plunger absorbing energy of piezo

  • ?????

Resources or Information Required but not Available

• • Dynamics of materials under very small displacement.

  • Gasket response

Schedule

• • Do a preliminary test with prototype

  • Parking

  • Update Gantt chart.

Budget (list amount spent and amount remaining)

• Spent

  • Two piezo stacks for testing - ~$150 total

  • Hardware for preload mechanism - ~$49

  • Pogo Pins ???

• Reminaning: ~< $4600

Progress on Report and Webpage

• • Finished Impact on Society

  • Re-designed main page