P16453Subsystem Design

Loading, Measurement, Control, and Test of a Journal Bearing Test Platform

Kris Kidder | John Dolan | Shay Stanistreet | Anthony Miuccio

Agenda

Restate Problem Statement

Team Vision

Functional Decomposition

Systems Architecture

Risk Assessment

Anti-Backlash Pre-Loading Concepts & Pugh Chart

Spring Arrangement Options

Rod Re-design Concepts & Pugh Chart

Feasibility Analysis

Oil Flow Investigation

Action Items

Problem StatementCurrently, RIT houses an ESH-1 compressor, which contains a particular type of fluid bearing, known as a journal bearing. These bearings are able to be tested on a rig which is a culmination of 2 years' work from other MSD teams. The first was tasked with the actual test rig design and structure, as well as a 1-D static load, and the second was tasked with creating a 2-D dynamic loading profile. Now, we've been tasked with providing additional measurement capability and final touches to some of the smaller issues on the existing rig. To name a few measurements we must collect:

Bearing Load

2-D Vibration Analysis

2-D Displacement Analysis

Oil Flow Rate

Film Thickness

In addition to these, we've also been asked to determine the eccentricity of the shaft, as well as the clearance between the shaft and bearing. We've also been tasked with modifying three bearings in order to test the rig with pre-determined results.

At the end of the project, we will be required to give our design documents, a working prototype, a technical paper, a poster, and we'll be presenting our project at ImagineRIT during the spring semester. We've been asked to complete this within a certain budget, using only LabVIEW, and to create a system that's local, convenient, and easy to use for somebody who isn't necessarily involved in its conception. Stakeholders include our MSD Team, Dresser-Rand, Dr. Kolodziej, as well as anybody interested in journal bearing tribology.

Team Vision - Subsystem Design

Plans for the subsystem design phase included:

Select Final Design for Backlash Elimination

Investigate Oil Flow Characteristics

Machine and Test Additional Bearings

Reintroduce Moog EMAs into our system

Full Disassembly of Test Rig

Of our available options, we utilized several iterations of Pugh Analysis to decide on a final design for backlash elimination. We’ve decided to go with a pre-loaded spring applying a median 1000 lbs. of force to the system, as well as a pin redesign to make the system more user-friendly. This should also benefit the machine operator when needing to frequently disassemble the test rig.

We are still in the process of investigating oil flow characteristics pertaining to journal bearings. We have very rudimentary calculations available, but more research will be going into determining critical parameters and more fundamental equations. We were fortunate enough to have been given additional bearings from a previous team, so redesigning them will be unnecessary. However, they will still need to be machined for our particular parameters.

The EMAs were returned from Moog, and were integrated back into the rig setup. We’ve done some basic exercises in moving the EMAs, but have not successfully mimicked the compressor load profile as of now. We were able to disassemble the rig partially, but due to time constraints, the rig will be reassembled at a different time.

Updated Functional Decomposition

Systems Architecture

Risk Assessment - Updated

Risk Assessment - Updated (cont.)

Anti-backlash concept 1

Anti-backlash concept 2

Anti-backlash concept 3

Anti-backlash concept 4

Anti-backlash concept 5

Anti-backlash Pugh Chart

Spring Arrangement Option 1

Spring Arrangement Option 2

Rod Redesign Concepts

Rod Redesign Pugh Chart

Feasibility Analysis - Rod Redesign

False Brinelling needs to be taken into account when choosing a joint.

False brinelling causes wear to occur at increased rate

Must be minimized as much as possible

EMA must be jogged fully and back.

Fully spreads out lubrication on metal parts to minimize false brinelling in th EMA

Metal on metal contact must be minimized in rod joint.

Rubber surface or lubed joint

Feasibility Analysis - Anti-backlash Spring System

- Assuming the system is vertical at its maximum loading scenario, the above free-body diagram will loosely represent the system.

- From basic statics, it can be found that W = 2500 lbs, and R = 500 lbs.

Feasibility - Anti-backlash (cont.)

Properties for a 2” x 2” bar, at length 5’, of A2 Tool Steel.

Feasibility - Anti-backlash (cont.)

Singularity Functions Important Values

Feasibility - Anti-backlash - Conclusions

- Winch is viable using designated lever arm design

- Lever Arm could be downsized for cost savings

- Current design allows for bending stress safety factor of 3.55

- Maximum deflection is less than ½-inch

- Springs available in many shapes, sizes, and strengths

- Proper sizing to be completed upon more detailed feasibility analysis

- Winches are available well beyond our weight requirements

- Also include intrinsic safety features to avoid slipping/unexpected loading disengagement

Oil Flow Investigation

From P15463 edge documentation

Oil Flow Investigation

Oil Flow Investigation

Action Items

Revise deliverables based on feedback

Choose materials to purchase for subsystem design

Button up all concept intricacies

Finish disassembling rig, and reassemble rig

Continue to familiarize ourselves with the existing software

Successfully run the load profile on the housing

Questions?