NAVAL POSTGRADUATE SCHOOL Monterey California , THESIS C9Z.575 Structural Considerations for Aircraft Payload Modification- P-3C Zero Fuel Weight Increase by Steven D. Culpepper March 199i Wu Thesis Advisor: Edward M. Approved for public release; distribution is unlimited. T253981 Jnclassified iecurity Classification of this page REPORT DOCUMENTATION PAGE a Report Security Classification Unclassified 1b Restrictive Markings a Security Classification Authority 3 Distribution Availability of Report b Declassification/Downgrading Schedule Approved for public release; distribution is unlimited. Performing Organization Report Number(s) 5 Monitoring Organization Report Number(s) a Name of Performing Organization 6b Office Symbol 7a Name of Monitoring Organization »Javal Postgraduate School (IfApplicable) 67 Naval Postgraduate School c Address (city, state, andZIPcode) 7b Address (city, state, andZIPcode) Monterey, CA 93943-5000 Monterey, CA 93943-5000 a Name of Funding/Sponsoring Organization 8b Office Symbol 9 Procurement Instrument Identification Number (IfApplicable) c Address (city, state, andZIPcode) 1 Source ofFunding Numbers Program ElementNumber | ProjectNo | TaskNo | WorkUnitAccessionNo STRUCTURAL CONSIDERATIONS FOR AIRCRAFT PAYLOAD 1 Tide(IncludeSecurityClassification) MODIFICATION- P-3H ZERO FUEL WEIGHT INCREASE 2 Personal Author(s) Steven D. Culpepper,LT USN 3a Type of Report 13b TimeCovered 14 Date ofReport (year, monlh.day) 15 Page Count Master's Thesis From To March 1991 77 6 SupplementaryNotation The views expressed in this thesis are those ofthe author and do not reflect the official ic-licy orposition ofthe Department ofDefense or the U.S. Government. Cosati Codes 18 Subject Terms (continue on reverse ifnecessary and identify by block number) Aircraft structures. Center section wing box, Euler-Bemoulli, Finite Element model. Structural analysis 9 Abstract (continue on reverse ifnecessary and identify by block number TheNavy isconsidering the feasibility ofincreasing thepatrol aircraftP-3C zero fuel weightenablingavionics and payload rowth. This analysis examines the consequences to the structural requirements of the center section wing box. Two solutions to the tructures fieldequations are investigated: asimplified hand solution forpreliminary feasibility calculationsanda more precise olution for design analysis. Together, thesolutions providea necessary check for the results. The simplified solution employs the luler-Bernoulli assumption which generates asetofintegrals expressed in termsoftheassumed displacements. These integrals, when ombined with simplified geometric shapes and symmetry, ultimatelyproduce adecoupled matrix solution. The precise solution uses PC based finite element method which simultaneously solves the fieldequations forbasic elements tobe linked togetherwith the ppropriate boundary conditions. Forthecurrent 135,000poundgross weight lg loadcondition, the internal stresses calculated by miteelementare in accord with thoseby simplified handcalculation. Extensions from this modeling will generatedesign criterion 3rthe target95,000poundzero fuel weightaircraftaswell as alternate flightor taxi conditions. Distribution/Availability of Abstract 21 Abstract Security Classification X unclassified/unlimited same as report DTICusen Unclassified 2a Name of Responsible Individual 22b Telephone(IncludeAreacode) 22c Office Symbol '.dward M. Wu (408) 646-3459 67 DFORM 1473. 84 MAR 83 APR editionmaybe used until exhausted security classification of this page All other editions are obsolete Unclassified Approved for public release; distribution is unlimited. Structural Considerations For Aircraft Payload Modification- P-3H Zero Fuel Weight Increase. by Steven Drew Culpepper Lieutenant, United States Navy B.S., United States Naval Academy, 1983 Submitted in partial fulfillment of the requirements for the degrc >f MASTER OF SCIENCE IN AERONAUTICAL ENGINEERING from the NAVAL POSTGRADUATE SCHOOL March 1991 ABSTRACT The Navy is considering the feasibility of increasing the patrol aircraft P-3C zero fuel weight enabling avionics and payload growth. This analysis examines the consequences to the structural requirements of the center section wing box. Two solutions to the structures field equations are investigated: a simplified hand solution for preliminary feasibility calculations and a more precise solution for design analysis. Together, the solutions provide a necessary check for the results. The simplified solution employs the Euler-Bernoulli assumption which generates a set of integrals expressed in terms of the assumed displacements. These integrals, when combined with simplified geometric shapes and symmetry, ultimately produce a decoupled matrix solution. The precise solution uses a PC based finite element method which simultaneously solves the field equations for basic elements to be linked together with the appropriate boundary conditions. For the current 135,000 pound gross weight lg load condition, the internal stresses calculated by finite element are in accord with those by simplified hand calculation. Extensions from this modeling will generate design criterion for the target 95,000 pound zero fuel weight aircraft as well as alternate flight or taxi conditions. in TABLE OF CONTENTS INTRODUCTION I. 1 PROBLEM DEFINITION 4 II. BOUNDARY CONDITIONS A. 4 FUSELAGE LOADS B. 4 WING LOADS C. 5 GROUND TAXI LOADS D. 6 CONTROL SURFACE LOADS E. 7 III. GENERAL SOLUTION TO P-3C 8 SOLUTION USING EULER-BERNOULLI ASSUMPTION A. 8 1. Summary of Field Equations 10 HAND CALCULATION IV. 21 WING MODELING A. 21 FUSELAGE MODELING B. 24 V. FINITE ELEMENT METHOD 30 PROCEDURES A. 31 1. Geometric Definition 31 2. Boundary Conditions 31 3. Model One 32 ALTERNATIVE SOLUTIONS (PROBLEM EXTENSION) VI. 35 A. BENEFITS OF THE DUAL APPROACH 35 1. Configuration Change 35 a. Example 1 36 2. Changing Material Properties 36 Example 2 37 a. RESULTS VII. 38 IV