| Created: 10/24/95 |
Updated: 4/18/97 |
INCREASING E-O RELIABILITY USING COMPUTER MODELING AND
SIMULATION
Project Number : C95-21
Point of Contact :
dbarker@calce.umd.edu
D. Barker, P. Mead
Objective
Currently, an integrated reliability approach which addresses actual electro-optic (E-O) design
architecture, materials, and geometries does not exist. This research program is directed at
providing such a modeling and simulation to address this discrepancy, and to link to the other
military and commercial physics-of-failure related efforts which have targeted electronic and
mechanical systems. With funding this program will deliver early prototype software that is
capable of evaluating the reliability of selected E-O devices.
Background
Modern military systems rely heavily on E-O systems which provide the capability for U.S.
forces to own the night. System readiness is strongly dependent upon the reliability of the E-
O systems. Each E-O subsystem and its individual components must be reliable without
unexpected failure during the system's service life. Two extremely important E-O devices, in
terms of military applications, are solid*-state Nd:YAG lasers and uncooled focal plane
arrays. These devices are key for all three military services in targeting and detection during
military operations. This project will develop the computer models and simulations, and the
associated methodologies and algorithms, as the framework necessary for all E-O devices. In
addition, more extensive work will be conducted to improve the reliability of these key E-O
devices.
Approach
The models and simulations will use a physics-of-failure approach to E-O system reliability.
Physics-of-failure is a physics and engineering based approach which addresses key failure
mechanisms and failure sites based on actual materials, environmental conditions, stresses,
design layout, and geometries. Physics-of-failure models and simulations are successfully
being implemented for electronic systems, both for military and commercial applications.
While work is continuing on physics-of-failure for electronic equipment, E-O systems have
not been addressed. This project will address this discrepancy, and link to the other military
and commercial physics-of-failure related efforts which have targeted electronic and
mechanical systems.
The current project is concentrating on only two E-O devices (uncooled focal plane arrays
and high power diode lasers used as pump sources for YAG lasers), but will serve as a
framework for other E-O devices to investigated later.
Work Accomplished
- Identified major failure mechanisms for high power diode lasers based on consultations
with major suppliers
- Completed FEA modeling of diode laser arrays using various heat sinking materials and
diode array geometries
- Investigated possible condition monitoring parameters for determining diode laser life
- Experimental design for phonon detection of operational laser diode devices
- Begun preliminary investigations of optical
fiber connector modes of failure
- Identified key material and geometric parameters for an IR uncooled detector FEA model
- Finish 3-D modeling of diode laser arrays on a variety of heat sink materials
- Identified key material and geometric parameters for ferroelectric monolithic uncooled
IR detector mechanical failure models
- Developed parametric based modeling tools for evaluating monolithic IR detector pixel
under thermal, vibration, shock, and processing loads to evaluate maximum deflections and
stresses in the structure.
