SystemModeler™ Applied - Modeling the Flap System of a Cessna

Anneli Mossberg, Olle Isaksson

Wolfram MathCore AB

Content

Introduction to failure modeling with Wolfram SystemModeler™

System overview

The Hydraulic System

The Model

Failure Analysis

Summary

Questions

Introduction to Failure Modeling with Wolfram SystemModeler™

Why use systems models to understand failures?

Increasingly difficult to understand systems as they grow larger and more complex

Using modeling and simulation we can answer questions like:

How will a control system behave when a component is malfunctioning?

Will a failure in a certain component manifest itself during a test procedure?

Can safety procedure A remedy failure B?

Reusable components

Design iterations

System Overview

The Flap System of Cessna 441 Conquest II

Why this particular system?

Multi-domain

Complex

Flaps are hinged devices located on the edge of the wings (see below)

Changing the angular position of the flaps changes the flight characteristics of the plane, for example in terms of lift and drag force

Advantages:

reduces the stress put on the aircraft

gives the pilot more time to react,

enables shorter runways

The pilot adjusts the flap position using the flap selector switch on the instrument panel. Possible positions:

Up - 0°

Takeoff - 10°

Approaching landing - 20°

Landing - 30°

The Hydraulic System

The Model

Overview

The top level model is hierarchical and contains 6 subsystems:

pilot

powerPlant

hydraulicPower

flaps

landingGear

electricalSystem

WSMModelData["FlapSystemFailureScenarios.Systems.Cessna441ConquestII"]

Figure 3.  Model diagram in SystemModeler™.

Hydraulic Systems

Figure 4. The flaps and hydraulicPower subsystems are based on the hydraulic circuit in the previous slide

hydraulicPower

Button[,WSMModelCenter["FlapSystemFailureScenarios.Systems.HydraulicPower"],Appearance->"Frameless"]

flaps

Button[,WSMModelCenter["FlapSystemFailureScenarios.Systems.Flaps"],Appearance->"Frameless"]

Failure Analysis

Failure Scenarios

A selection of the modeled scenarios:

Nominal operation

Hydraulic failure

Mid-air electrical failure

Electrical failure with a safety procedure

Nominal Operation

Hydraulic Failure

A pipe is leaking in the flap subsystem. The failure was injected using component based, drag and drop modeling.

Button[,WSMModelCenter["FlapSystemFailureScenarios.Systems.Flaps"],Appearance->"Frameless"]

Mid-Air Electrical Failure

The up-solenoid in the flap control valve has a pin short.

Button[,WSMModelCenter["FlapSystemFailureScenarios.Systems.Flaps"],Appearance->"Frameless"]

Electrical Failure with a Safety Procedure

The pilot puts the flap selector switch in the landing position and resets the circuit breaker.

Button[,WSMModelCenter["FlapSystemFailureScenarios.Systems.Pilot"],Appearance->"Frameless"]

Summary

Failure analysis after a sequence of command

Fault code coverage analysis

Testing safety procedure designs

Conclusion: modellig has great potential in failure analysis

Additional information

Modeling Aircraft Flap System Failure Scenarios with SystemModeler: http://blog.wolfram.com/2014/09/29/modeling-aircraft-flap-system-failure-scenarios-with-systemmodeler/

New in SystemModeler™ 4: http://www.wolfram.com/system-modeler/new-in-4/

Wolfram Hydraulic library: http://www.wolfram.com/system-modeler/libraries/hydraulic/

SystemModeler™ library store: http://www.wolfram.com/system-modeler/libraries/

Online demand course: http://www.wolfram.com/training/videos/ENG034/

Online aircraft engineering course for Cessna 441 Conquest II: http://www.cessnaconquest.net/

Accident report of a failed limit switch on a Cessna 182Q: http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20001214X43101&key=1

Accident report of a mechanical failure on a Cessna 421B: http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20110430X60514&key=1

Accident report of a hydraulic leakage on a Cessna 560: http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20061222X01843&key=1

Thank you for listening!

Questions?

Needs["WSMLink`"];