P18371: Meggitt Brake Simulator
/public/

Problem Definition

Table of Contents

Team Vision for Problem Definition Phase

Team Plans

Accomplishments

Project Summary

A brake simulator is a hydro-mechanical assembly that is able to replicate the brake system of an aircraft. This simulator will mimic the brake performance of different sizes for a variety of brake assembly testing plans. The simulator must be able to integrate with other aircraft component simulators as well, such as a hydraulic rig. Brake simulators are used in order to collect accurate data without testing an actual brake assembly. The data for a simulator will be compared to physical brake test data in order to verify the simulated output.

Meggitt Aircraft Braking Systems is in need of a simulator mimic brake assembly compliance and mechanical stiffness of their braking systems. The current setup regards two components plumbed together on a table-top with brake assemblies hung off the sides. The simulator will eliminate the need for bulky assembly and physical product testing. The simulator’s control system will show the hydraulic load generated from the brake assembly, as well as permit an operator to quickly and easily modify the simulation.The operator must be able to monitor the system parameters behind a safety shield while viewing the test through a sight window. The apparatus must be maneuverable through a 32” door by a single person. Installation must require less than 30 minutes, pressure changes must occur within an 8 hour period, and air must be bled out for disconnection within (X) amount of time.The simulator must be able to operate over a range of 0 to 5000 psi and 1 million maximum pressure cycles. The final output will be a graph of volumetric displacement versus a hydraulic pressure curve.

Apparatus must comply with the following standards: NEMA, CE, SAE AS4716, SAE AS6235, SAE AS4365, SAE AS4375, SAE AIR5372 and MIL-PRF-5606 or AS1241.

Use Scenarios

  1. Test existing rigs used at Meggitt for calibration
  2. Evaluate expected performance of a particular type of aircraft brake
Main AABS Use Scenario for Brakes Test

Main AABS Use Scenario for Brakes Test

Project Goals and Key Deliverables

Stakeholders

Stakeholder Position
Meggitt - Kyle Berkowitz COE Engineer
Meggitt PLC Key User
Meggitt's Aviation Customers Brake users\owners
Harold Paschal Academic Advisor
MSD Team AABS System Developers

Constraints

These constraints are elaborated and investigated through comparing engineering requirement to Meggitt's stated requirements for the AABS system below.

Customer Requirements (Needs)

Meggitt has requested the AABS system to replace their existing brakes testing method. Currently brakes engineers attach non-serviceable, or otherwise unusable brakes assemblies to their hydraulic test rig. Usually, this is done for one of two cases:

As Meggitt uses only non-serviceable brake assemblies, if none are available, these tests cannot be run. Additionally, these assemblies are large, bulky and non-consistent between runs, as they are no longer in use and likely incapable of producing accurate pressure vs. displacement output.

Current State

Therefore Meggitt has attempted several prototype designs to resolve this issue. Their first design, produced in 1990, aimed to add variability to the simulator. Though never fully developed, this prototype was capable of replicating various brakes designs by having a set of spring disks swapped at the engineer's request.

Prototype c. 2017 to mimic mid-sized Business Jet Brake. Similarly, spring disks were used to mimic brakes performance when hydraulic pressure is applied. However, this design was only useful for mid-sized brakes assemblies, and thus not addressing Meggitt's need for a universal simulator, and example of a high cost, low value functional prototype.

In response to this state, the following are Meggitt PLC's general requirements as to the function and form of the AABS system.

Type CR Meggitt’s Customer Requirements CAI
Footprint CR 1 Transportable 5
CR 2 Compact 5
Setup CR 3 Quick Installation Time 3
CR 4 Set time to alter pressure/displacement settings 3
Compatibility CR 5 Configure to Meggitt’s existing hydraulic lines 5
CR 6 Compatible with common aircraft brake fluids 5
Safety CR 7 Safe for user 5
CR 8 Consistent with existing US and European regulation 5
Function CR 9 Easily Configurable to various brake specs 5
CR 10 Pistons & Rod Seals Specs Standardized 5
CR 11 Easily free the system of air 4
CR 12 Design to any Displacement vs. Pressure curve 5
CR 13 Ability to tune fill rate 5
CR 14 Reliable and accurate 5
CR 15 Long term usage 4
CR 16 Ability to maintain and repair 5
CR 17 Resistance to indoor environment/hydraulic fluids 5
Interface CR 18 Uses commercially Available Software 1
IP Concerns CR 19 Limited IP in development 1

Note: Upon visit to Meggitt, Kyle suggested 'Priority' be represent in a more defined manner, thus the team implemented the Customer Applicability Index (CAI). This scales the customer ratings from 1 to 5, with 5 being most critical.

Engineering Requirements (Metrics & Specifications)

Engineering requirements for the development of the AABS system were determined through interpretation of Meggitt's prescribed customer requirements, as well as email correspondence and a customer interview with Kyle Berkowitz and Ankit Prasad, engineers at Meggitt working with the team to develop the brake assembly simulator.
Type ER Source AABS Engineering Requirements Unit Ideal Marginal Improvement Test
Footprint ER 1 CR 1, CR 2 Max width of 32" in 28 32 minimize tape measure
ER 2 CR 1, CR 2 Weigh less than 100 lbs lbs 80 60 minimize NIOSH compliant
Setup ER 3 CR 3, CR 9 Setup modification complete within 30 minutes minutes 15 30 minimize timer
ER 4 CR 3, CR 4 8 hours to fully configure AABS hour 1 4 minimize timer
ER 5 CR 5, CR 12, CR 14 Common set-up parameters result in consistent output curve error 100% 95% maximize curve error
Safety ER 6 CR 5, CR 7, CR 15, CR 16 No pinch points count 0 0 minimize visual check
ER 7 CR 7, CR 8 NEMA & CE compliant Y/N compliant compliant X Read guidelines
ER 8 CR 5, CR 7, CR 8, CR 10, CR 15 AS4716 Compliant; O-Ring and Gland Spec Y/N compliant compliant X Read guidelines
ER 9 CR 5, CR 7, CR 8, CR 10, CR 15 AS6235 Compliant; O-Ring and Gland Spec Y/N compliant compliant X Read guidelines
ER 10 CR 7, CR 16 Protective shield must contain all potential shrapnel count 0 0 minimize visual check
Rig Compatibility ER 11 CR 5, CR 7, CR 10 AS4375 Style-E Fitting Ends (Tube Size: OD: 0.375'') Y/N compliant compliant X Read guidelines
ER 12 CR 5, CR 6 Capable of using Red Oil; MIL-PRF-5606 Y/N Y Y X system compatibility
ER 13 CR 5, CR 6 Capable of using Phosphate Ester: AS1241 Y/N Y Y X system compatibility
ER 14 CR 3, CR 5, CR 7, CR 13 Hydraulic inlet must have 0.052’’ restrictor in 0.052" 0.052" ideal caliper
Function ER 15 CR 7, CR 11, CR 14, CR 15 Must bleed the system of air within 5 minutes minutes 1 5 minimize timer
ER 16 CR 5, CR 9, CR 12, CR 13 Reach max pressure of 5000 psi psi 4500 5000 maximize range pressure transducer
ER 17 CR 14, CR 15 Accelerated Life Testing Predict 1M Pressure Cycles count 1 M 1 M maximize Accel. Life Cycle Test
Structure ER 18 CR 7, CR 14, CR 15, CR 16, CR 17 Components made of SAE/MIL Spec Materials Y/N Y Y X design to ER
ER 19 CR 7, CR 8, CR 14, CR 15 Minimum Factor of Safety of 1.2 [-] 1.5 1.2 maximize ANSYS
Interface CR 20 CR17 Utilize C based architecture (MATLAB, Python) Y/N Y Y X design to ER

The National Institute for Occupational Safety and Health (NIOSH) is a division of the Centers for Disease Control and Prevention (CDC)

House of Quality

The HOQ evaluates the congruence between Meggitt's proposed requirements and the team's derived engineering requirements as gathered from the aforementioned CR's. As such, by evaluating the relationship between ERs and CRs for the AABS project, relative weighting is applied to each engineering requirement:
AABS House of Quality

AABS House of Quality

Image derived from: House_of_Quality.xlsx

From this, ERs can be sorted via relevance to the project.

Weight Engineering Requirement ER No.
8.33% Components made of SAE/MIL Spec Materials ER 18
8.06% AS4716 Compliant; O-Ring and Gland Spec ER 8
8.06% AS6235 Compliant; O-Ring and Gland Spec Y ER 9
7.05% Reach max pressure of 5000 psi ER 16
6.87% Minimum Factor of Safety of 1.5 ER 19
6.59% Must bleed the system of air within 5 minutes ER 15
6.50% No pinch points ER 6
6.50% Hydraulic inlet must have 0.052’’ restrictor ER 14
5.95% AS4375 Style-E Fitting Ends (Tube Size: OD: 0.375'') ER 11
4.58% Capable of using Red Oil; MIL-PRF-5606 ER 12
4.58% Capable of using Phosphate Ester (Skydrol): AS1241 ER 13
4.12% 1 million max pressure cycles ER 2
4.12% Weight less than 100 lbs ER 5
4.12% Accelerated Life Testing Predict 1M Pressure Cycles ER 17
3.66% NEMA & CE compliant ER 7
3.39% Protective shield must contain all potential shrapnel ER 10
3.21% Maximum width of 32" ER 1
2.75% Setup modification complete within 30 minutes ER 3
1.10% 8 hours to fully configure AABS ER 4
0.46% Utilizes C based architecture (MATLAB, Python) ER 20

From the table shown above it is evident that high level system characteristics, such as max psi level, hydraulic fitting requirements and safety features, such as the bleed air system, are weighted relatively higher than items such as configuration time and IP specifics.

Outputs and Destination

For P18371 and our AABS system project, stored data can be found in the Problem Definition Documents directory.

Provide input to the risk management process.

Design Review Materials

Design Review: The Problem Definition Review PowerPoint as presented 01/30/2018. The CR, ER, HOQ, Preliminary Schedule, and Risk Management charts from the powerpoint were printed for audience handouts.

Plans for next phase

Individual and group actions towards the next phase will be specified once the team meets with the sponsor 2/16/2018 in Akron, OH.


Home | Planning & Execution | Imagine RIT

Problem Definition | Systems Design | Preliminary Detailed Design | Detailed Design

Build & Test Prep | Subsystem Build & Test | Integrated System Build & Test | Customer Handoff & Final Project Documentation