Shock & Vibration:
Case Study
For Northrop Grumman Information Systems
LX Course: 3rd Quarter 2011
The presentation material is a proprietary property of Luxea & Dunamis Inc.
Contact the company for appropriate distribution.
Luxea Inc. / Dunamis Tech Inc.
2 The presentation material is a proprietary property of Luxea & Dunamis Inc. Contact the company for appropriate distribution.
Week 1 - Overview and Introduction
SHOCK & VIBRATION FOR ELECTRONICS I
Luxea Training Courses
This is the introductory course for shock and vibration for electronics. It covers the
basic shock and vibration theory with focus on practical engineering applications.
SHOCK & VIBRATION FOR ELECTRONICS I: CASE STUDY
This is the follow-on application course of the Shock and Vibration for Electronics I
with several case studies extracted from previous projects.
HEAT TRANSFER FOR ELECTRONICS I
This course covers the basic heat transfer theory and focuses mainly on practical
application to electronics packaging design and analysis.
HEAT TRANSFER FOR ELECTRONICS I: CASE STUDY
This is the follow-on application course of the Heat Transfer for Electronics I with
several case studies extracted from previous projects.
Shock &
Vib
ration
Heat
Tra
nsfe
r
Goal – Efficiency
4
“You’ve been charging me 2
weeks worth of consulting for
a 4 hour analysis with your
software”
“You’ve been charging me 2 weeks of consulting
for a 4 hour analysis with your software”
ME Lead, NGIS ESL
Random vs. Sinusoidal Vibrations
Shock and Vibration for Electronics I
• Offered in December 2010
• Basic fundamental theories established
• Practical application-focused 3-day seminar
• Use of LuxCalc Tools
Why Case Study Course?
5
Apply S&V seminar into real problems
• Basic understanding acquired
• 3-day intense seminar too short
• Limited practice due to time constraints
• Practical seminar but still need ties to NG project and guidelines
DESCRIPTION
Course Syllabus
This is a 12-week follow-on case study course of Shock and Vibration for Electronics I.
This course builds on the basic engineering mechanics theories and applications learned
from the previous course (including strength of material, shock and vibration) and applies
them to electronics packaging through several case studies. By working with the real
engineering problems, students would develop confidence in solving other mechanical
engineering problem and be able to evaluate complex engineering problems prior to or in
parallel with FEA work.
DAILY COURSE PLAN
At the beginning of class session, the instructor would briefly discuss the homework com
ments posted on the Blog by the students. The problem statement is presented, and the
solution approach and the assumptions are thoroughly discussed. Setting up the solution
process is the critical to all engineering problem solving. The solution steps with LuxCalc
Tools will be done together to fully engage the student participations. Students should
have an access to laptops.
TOOLS
During the course, we will be using Luxea’s LuxCalc Tools System to solve and
analyze the test case problems. The software will be available for download through
NGIS ESL server. The LuxCalc Tools System includes several modular calculators for
mechanical engineering in a comprehensive suite. The continuously growing system
includes engineering calculator tools commonly used in mechanical engineering
disciplines: thermal, dynamic and stress analyses.
BLOG
All of the homework problems assigned in this course will be posted on Luxea’s website
along with the solutions. Feel free to ask questions or leave comments about the
homework problem on the blog. Discussion amongst yourselves is highly encouraged
and the instructors will frequently leave a comment as well. The solutions will be posted
on Thursday of every week.
Luxea HW Blog: www.luxea.com/Blog/Categories
Blog
SCHEDULE
Week Topic/Case Study HW
1 Overview and Introduction
2 Review of Shock & Vibration for Electroincs I
3 Case I: Transportation shock and vibration
4 Case II: Rack on isolators – pulse shock
5 Case II: Rack on isolators – drop shock
6 Case II: Rack on isolators – random vibration
7 Case II: Rack on isolators – multi-DOF and nonlinear effect
8 Case III: Chassis/PCB – shock
9 Case III: Chassis/PCB – random vibration
10 Case IV: Transit Case Analysis – MIL-HDBK-304
11 Case V: Transit Case Analysis – Nonlinearity
12 Summary and Closing
Problem Statement
The package had been qualified
to MIL-STD-810F truck vibration.
Alternative transportation
proposed: C5 & C130 aircrafts
Can we show that the air
transportation is acceptable?
Use of LuxCalc Vibration for
comparisons
Various input spectra result in
surprising results
Transportation Random Vibrations
NG package responses to various MIL-STD-801F transportation
random vibrations are compared.
Case Study II
Equipment Rack System
Shock and vibration analysis of an equipment rack system
mounted on coil isolators
Shock pulse and drop shock per
MIL-STD-810F
Random vibration per MIL-STD-
810F
One and two DOF models,
various parameter effects
Use of LuxCalc Tools for quick
evaluations
This case study demonstrates the
influence of various paremters.
Case Study III
Module with Power PCB
Shock and vibration analysis of a chassis with a CCA, mounted
with or without isolators
Conduction-cooled 3U Compact
PCI PCB
PCB Assembly mounted to
housing with Wedge-lok
Housing mounted with or without
isolators
Analysis using LuxCalc Tools
Effectiveness of isolators in shock
and vibration demonstrated
Case Study IV
Connector in Transit Case
Transit drop analysis of a heavy payload in transit
case
36 inch drop shock per MIL-STD-
810F procedure IV
Packaged protected by Polyether
foams
MIL-HDBK-304 data and
procedures for analysis
Use of LuxCalc Tools Shock for
checks
MIL-HDBK-304 & LuxCalc Tools
Payload in Transit Case
Transit drop analysis of a package in transit case using
MIL-HDBK-304.
Case Study V
Connector in Transit Case
Transit drop analysis of a heavy payload in transit
case
18 inch drop shock per MIL-STD-
810F procedure IV
Packaged protected by
Polyethylene in wooden crate
Some FEA results for nonlinearity
may be utilized.
Use of LuxCalc Tools Shock for
detail evaluations
Highly nonlinear foam-payload
dynamics
Payload in Transit Case
Transit drop analysis of a connector in transit case
Case Study I Overview
• An NG Package was designed to be transported by truck.
• The package was fully qualified to MIL-STD-810F environments.
• Customer asks, “can we ship via air?”
The package had been qualified
to MIL-STD-810F truck vibration.
Alternative transportation is
proposed: C5 & C130 aircrafts
Can we show that the air
transportation is acceptable?
Customer needs to make a
decision in a day.
Various input spectra result in
interesting results
Background
1. Review all transportation-related (non-operational) specifications
• Temperature, humidity, altitude, shock and vibration
• Only the random vibration is affected.
2. Compare input random vibration spectra – truck, C5 and C130
• PSDin vs. frequency
• Input grms
3. Identify the subassembly level qualified
• Package system as a whole above
the isolators
4. Evaluate the response of the subassembly.
• Calculate and compare its response to the random spectra
Evaluation Process
• Compare the environmental conditions between C130, C5
and Truck transportations.
Random Vibration Spectra
Category 7 (jet air) Category 8 (propeller)
Category 4 (truck)
Qualified to
Proposed
• Comparison of three transportation modes (notional)
0.1 g2/Hz
0.01 g2/Hz
0.015 g2/Hz
0.003 g2/Hz
Input Curve Comparison
• Below isolator - pallet: m1 = 5,900 lbs, K1 = 10e6 lb/in
• Above isolator - payload: m2 = 19,500 lbs, K2 = 5e5 lb/in
• Model damping: I = 15%, II = 5%,
m1 = 19,500 lbs
m2 = 5,900 lbs
K2 = 500,000 lb/in
1
2
LuxCalc Input
• Input grms = 1.136
• Response grms = 1.066
• Peak PSD at fI = 0.190 g2/Hz
Truck PSD
Truck
Response to Truck Vibration
• Input grms = 2.875
• Response grms = 0.966
• Peak PSD at fI = 0.1268 g2/Hz
C130 PSD
C130 Aircraft
Response to C130 Aircraft Vibration
• Input grms = 2.111
• Response grms = 0.357
• Peak PSD at resonance (fI) = 0.038 g2/Hz
C5 PSD
C5 Aircraft
Response to C5 Aircraft Vibration
• Comparison of three transportation mode responses
Response Curve Comparison
Truck C130 Aircraft C5 Aircraft
Response Comparison
• Comparison of three transportation mode responses
Response Curve Comparison
Response Curve Comparison
• Input grms is higher in C-130 and C5 vibrations than the truck’s
spectra.
•The important parameters are response grms and PSDin at
resonance – both parameters are lower in both aircraft
transportations.
• It is concluded that the air transportation via C130 or C5 will cause
less vibration loads.
Truck C-130 C-5
Input grms 1.194 2.875 2.111
Response 1 grms 1.066 0.966 0.357
PSD at resonance 0.190 0.127 0.038
Case Study I – Summary and Conclusions
Case Study I – Summary and Conclusions
Luxea Inc. / Dunamis Tech Inc.
25 The course material is a proprietary property of Luxea & Dunamis Inc. Contact the company for appropriate distribution.
Shock & Vibration: Case Study
26
