DTIC ADA639787: A Deterministic Approach for Characterizing Wave Impact Response Motions of a High-Speed Planing Hull

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by  Defense Technical Information Center

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Naval Surface Warfare Center
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S Carderock Division
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NSWCCD-23-TM-2012/05 January 2012
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A DETERMINISTIC APPROACH FOR
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CHARACTERIZING WAVE IMPACT RESPONSE

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The Columbia Group
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ri Kelly D. Haupt and Donald R. Jacobson
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Cng DISTRIBUTION STATEMENT A: Approved for public release;
Wni distribution is unlimited.
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A DETERMINISTIC APPROACH FOR CHARACTERIZING
WAVE IMPACT RESPONSE MOTIONS OF A HIGH-SPEED
PLANING HULL
NSWCCD-23-TM-2012/05

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4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER
A Deterministic Approach for Characterizing Wave Impact
Response Motions of a High-Speed Planing Hull
5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S) 5d. PROJECT NUMBER
Michael R. Riley, Kelly D. Haupt, Donald R. Jacobson
5e. TASK NUMBER

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT

NUMBER

NAVSEA Carderock NSWCCD-23-TM-2012/05
Surface Warfare Center Division
Combatant Craft Division
2600 Tarawa Court, #303
Virginia Beach, Virginia 23459-3239
9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S)
Office of Naval Research ONR
Sea Warfare Applications Division
875 North Randolph Street, Arlington, VA 22203-1995 11. SPONSOR/MONITOR’S REPORT

12. DISTRIBUTION / AVAILABILITY STATEMENT

DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.

13. SUPPLEMENTARY NOTES

14. ABSTRACT
This report presents a new deterministic approach to analyzing wave impact data for high speed planning hulls. Full
scale data is presented that illustrates how individual wave encounters may be defined and categorized according to
impact sequence of events, and that the peak accelerations may vary linearly with defined parameters for subsets of
wave slam types. The report builds on lessons learned from historical stochastic analysis methods, and provides a
new analysis process that enhances the understanding of key elements associated with craft seaworthiness, including
hull design loads, component ruggedness, and crew or passenger comfort and safety.

15. SUBJECT TERMS
Peak acceleration Wave slam Planing hull Data analysis

16. SECURITY CLASSIFICATION OF: 17. LIMITATION 18. NUMBER 19a. NAME OF RESPONSIBLE PERSON
OF ABSTRACT OF PAGES
Kelly D. Haupt
a. REPORT b. ABSTRACT c. THIS PAGE 19b. TELEPHONE NUMBER (include area
Unclassified Unclassified Unclassified See 12. 35 code)
757-462-4136
Standard Form 298 (Rev. 8-98)

Prescribed by ANSI Std. Z39.18
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Contents
Page
Figures ........................................................................................................................................... iv
Tables ............................................................................................................................................ iv
Administrative Information ..........................................................................................................v
Acknowledgements ........................................................................................................................v
Summary .........................................................................................................................................1
Introduction ....................................................................................................................................1
Background ............................................................................................................................ 1
Deterministic Analysis Approach .......................................................................................... 2
Typical Acceleration Data ..................................................................................................... 3
Characteristics of Individual Wave Slams ..................................................................................5
Individual Wave Slam Events................................................................................................ 5
Sequence of Events ................................................................................................................ 6
Wave Slam Parameters .......................................................................................................... 7
Type Alpha Slam ................................................................................................................. 10
Type Bravo Slam ................................................................................................................. 12
Type Charlie Slam ............................................................................................................... 12
Peak Vertical Acceleration Trends.............................................................................................16
Linear Regression ................................................................................................................ 16
Wave Slam Pulse Shapes ..................................................................................................... 17
Scaling Relationship ............................................................................................................ 17
Parametric Trends ................................................................................................................ 18
Observations .................................................................................................................................22
Conclusions ...................................................................................................................................23
Symbols, Abbreviations, and Acronyms ....................................................................................24
References .....................................................................................................................................25
Distribution ...................................................................................................................................26

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Figures
Page
Figure 1. Vertical Acceleration at LCG of a 36 Foot Craft .............................................................3
Figure 2. Planing Craft Peak Acceleration Histogram.....................................................................4
Figure 3. Peak Accelerations Plotted Largest to Smallest ...............................................................4
Figure 4. Cumulative Distribution Plot with A Average Values .................................................4
1/N
Figure 5. Individual Wave Encounters and Wave Slam Events ......................................................5
Figure 6. Wave Slam Sequence of Events .......................................................................................7
Figure 7. Wave Slam Parameters .....................................................................................................8
Figure 8. Examples of A and A Values ......................................................................................9
X ZT
Figure 9. Angular Acceleration at the LCG ...................................................................................10
Figure 10. Type Alpha Slam Sequence of Events .........................................................................11
Figure 11. Type Alpha Precursor Non-Slam Event .......................................................................11
Figure 12. Type Bravo Wave Slam Sequence of Events ...............................................................12
Figure 13. Type Charlie Wave Slam Sequence of Events .............................................................13
Figure 14. Peak Vertical Acceleration Linear Trends ...................................................................16
Figure 15. Normalized Wave Slam Pulse Shapes ..........................................................................17
Figure 16. A versus A Wave Slam Parameters .........................................................................18
X ZT
Figure 17. Type Alpha Wave Slam Trends ...................................................................................19
Figure 18. Type Bravo and Charlie Wave Slam Trends ................................................................20
Figure 19. Impact Energy Partitioning...........................................................................................21

Tables
Page
Table 1. Wave Slam Characteristics ..............................................................................................14
Table 2. Wave Slam Parameters ....................................................................................................15

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Administrative Information
The work described in this report was performed by the Combatant Craft Division (Code
23) of the Ship Systems Integration and Design Department at the Naval Surface Warfare
Center, Carderock Division (NSWCCD). This effort was sponsored by the Office of Naval
Research, Sea Warfare Applications Division (Code 333), Arlington, VA, and funded under
document numbers N0001408WX20581 and N001408WX20619.

Acknowledgements
The authors would like to thank Dr. Peter Paul Rispin, Office of Naval Research, for
directing the investigation of combatant craft wave-slam physics and dynamic analysis response
methodologies, and Mr. Dan Sheridan, DJS Associates, Inc., for his insights and management
oversight. Dr. Timothy Coats, Director of Research and Development, Combatant Craft
Division, was also instrumental in leading the analysis project, and his earlier work established a
solid foundation for continuing work.

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Summary
This report presents a new approach for analyzing acceleration response motions of high-
speed planing craft in waves. These motions are of interest because a broader awareness and a
better understanding of cause and effect physical relationships in high-speed wave impacts could
be applied in craft design or comparative craft system evaluations to address multiple factors
associated with seaworthiness, including hull design loads, stability, component ruggedness, and
crew or passenger comfort and safety.
A new deterministic analysis methodology is presented that characterizes the rigid-body
responses of a craft in terms of acceleration, velocity, displacement, and rotation motions during
each wave slam event. Time-history comparison plots of various individual wave impact events
are presented, new wave impact parameters and types of impacts are defined, and the results of
regression analyses are presented. Typical full-scale acceleration data presented in the report
indicates that individual wave encounters can be defined and categorized according to wave
impact sequence of events, and that the peak rigid body accelerations vary linearly with defined
parameters for subsets of wave slams. The limitations of these results are summarized and
further research is suggested for achieving a broader level of knowledge for future applications.

Introduction
Background
Reference 1 presents a summary of lessons learned from historical stochastic analysis
methods that transition the randomness of ocean waves and full-scale trials data to useful average
peak acceleration values. In reference 2 a four-step process was recommended as a standard
approach for computing the average of the 1/nth highest acceleration when analyzing
accelerometer data recorded during full scale or model scale trials of small craft. Three criteria
were presented that preclude the subjectivity of classical peak-to-trough methods, and lead to
consistent results by different researchers across multiple organizations. The three criteria
included low pass data filtering at 10 Hz, a peak-to-trough vertical threshold equal to the
acceleration record RMS value, and a peak-to-trough horizontal threshold equal to 0.5 seconds
Current hull design methodologies and seakeeping criteria are based on the solid
foundation of understanding related to the randomness of ocean waves. It is envisioned that
previous stochastic methods coupled with the new analysis approach presented in this report will
help researchers, designers, engineers, builders, and operators increase their awareness and
understanding of the dynamics of high-speed wave impacts for planing hulls. The increased
awareness and understanding could have broad applications for improved standard processes,
including structural design, correlation with computational modeling and simulation
methodologies, correlation of full-scale and scale-model test data, comparative evaluations of
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different craft, and development of criteria for improved ruggedness and personnel comfort and
safety.
Deterministic Analysis Approach
A deterministic analysis approach is one that assumes that relationships in a physical
system involve no randomness in the development of a future state. These approaches typically
yield mathematical equations that produce the same output for a given set of starting conditions.
An interesting example that illustrates the transition from stochastic to deterministic approaches
is Savitsky’s original equation relating average peak acceleration to significant wave height and
craft speed (reference 3).
H   B V 2 
( )
a ≈ C 1/3 +0.084 t 5−  
cg      Equation (1)
 b   10 L 
where:
a −average peak vertical acceleration at CG
cg
H −significant wave height
1/3
V −craft speed
b−beam
t −trim
B−deadriseangle

The term C is a constant times the length-to-beam ratio divided by the beam loading
coefficient.
Equation (1) presents a relationship between initial condition parameters such as craft
structural dimensions, significant wave height, and craft speed, to predict an outcome, in this
case the average of all the peak accelerations observed during a given time period. This equation
leads to an interesting scaling relationship when you consider the same craft operating at
different speeds in different significant wave heights. By dividing equation (1) by itself for
different sea state and speed conditions “i” and “j”, we obtain the following approximate scaling
relationship.

a H V2 
cgi ≈constant 1/3i  i 
acgj H1/3j V2j  Equation (2)

Equation (2) indicates that the ratio of the acceleration responses is in direct proportion to
the ratios of the potential and kinetic energies associated with conditions i and j. This suggests
that a cause-and-effect relationship may exist not only for an average of many waves, but for
response amplitudes of individual waves as well.

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