geardropsim a tool for simulating landing gear drop tests. dr. dan retief phd (mech. eng.)
TRANSCRIPT
Background / History 1982 – BE Mechanical – University of Pretoria 1983-1985 National Service in SA Air Force 1985 – Complete ME at University of Pretoria 1989 – PhD Mechanical Engineering. 1983 – 1986 Armscor – A-Vehicles. 1987 – 1990 Armatron Systems . 1990 – 1993 Aero Projects and Epsilon Eng. 1994 Settle in NZ – Computer Programming Fisher & Paykel Laundry – Washer Dynamics and
Structures Pacific Aerospace Ltd – 750 XL Ag conversion, IFR,
electric upgrade. Alpha Aviation – Chief Designer 2009 – Started Aero Design Ltd
Aero Design’s Office400 Raynes RoadRD 2Hamiltonwww.aerodesign.co.nz
Component Element Method
Fmvdt
d)(
Fdt
ydm
dt
dvm
2
2
Newton’s Second Law
Reference: The Component Element Method in DynamicsSamuel LevyAndJohn Wilkinson
Component Modelling Elements Mass Spring Damper
Simple mass-spring-damper system.
Free body diagram.
ymyckyF
Finite Difference Equations
0011
2101
2)(
2Fky
t
yyc
t
yyym
Solving for y1
01202
2
1 )(2)(
2
2)(
1Fy
t
m
t
cyk
t
m
tc
tm
y
Algorithm
Masses as objects with attach points Force elements as objects with nodes Calculate starting values for all object
positions and velocities Calculate attach point location and
velocities from mass location and orientation.
Calculate forces in force elements Calculate mass acceleration, velocity
and next position from sum of forces on it.