Contents
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
STRUCTURAL DAMAGE TOLERANCE
USAF Experience in the Qualification of Composite Structures–J. w. LINCOLN . . . . . . . . 3
A Review of Some Key Developments in the Analysis of the Effects of Impact Upon
Composite Structures–R. OLSSON, L. E. ASP, S. NILSSON, AND A. SJOGREN . . . . . . . . . [2
Certificate Cost Reduction Using Compression-After-Impact Testing–T. C. ANDERSON . 29
SKIN-STRINGER BEHAVIOR
Mechanisms and Modeling of Delamination Growth and Failure of
Carbon-Fiber-Reinforced Skin-Stringer Panels–E. GREENHALGH, S. SINGH, AND
K. F. NILSSON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Parametric Study of Three-Stringer Panel Compression-After-lmpact
Strength–c. Q. ROUSSEAU, D. J. BAKER, AND J. DONN HETHCOCK . . . . . . . . . . . . . . . . . 72
A Method for Calculating Strain Energy Release Rates in Preliminary Design of
Composite Skin/Stringer Debonding Under Multiaxial Loading–R. KRUEGER,
P. J. MINGUET, AND T. K. O’BRIEN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
ROTORCRAFT AND PROPELLER STRUCTURAL QUALIFICATION ISSUES
Fail-Safe Approach for the V-22 Composite Proprotor Yoke–L. K. ALTMAN, D. J. REDDY,
AND H. MOORE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
RAH-66 Comanche Building Block Structural Qualification Program–A. DOBYNS,
B. BARR, AND J. ADELMANN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
The Effects of Marcel Defects on Composite Structural Properties–A. CAIAZZO,
M. ORLET, H. McSHANE, L. STRAIT, AND C. RACHAU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
Influence of Ply Waviness on Fatigue Life of Tapered Composite Flexbeam
Laminates–~. 8. MURRI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
Structural Qualification of Composite Propeller Blades Fabricated by the Resin
Transfer Molding Process–s. L. SMITH, AND J. L. MATTAVI . . . . . . . . . . . . . . . . . . . . 2 i0
BOLTED JOINT ANALYSIS
Three-Dimensional Stress Analysis and Failure Prediction in Filled Hole
Laminates–E. v. IARVE AND D. H. MOLLENHAUER . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Damage-Tolerance-Based Design of Bolted Composite Joints–x. QING, H.-T. SUN,
L. DAGBA, AND F.-K. CHANG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
Open Hole Compression Strength and Failure Characterization in Carbon/Epoxy
Tape Laminates–rE BAU, D. M. HOYT, AND C. Q. ROUSSEAU . . . . . . . . . . . . . . . . . . . . 273
The Influence of Fastener Clearance Upon the Failure of Compression-Loaded
Composite Bolted Joints—-A. J. SAWlCKI and P. J. MINGUET . . . . . . . . . . . . . . . . . . . . . 293
Characterizing Delamination Growth in a 0~ ~ Interface–R. H. MARTIN AND
C. Q. ROUSSEAU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
New Experiments Suggest That All Shear and Some Tensile Failure Processes are
Inappropriate Subjects for ASTM Standards–M. R. PIGGOTT, K. LIU, AND
J. WANG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
Effect of Friction on the Perceived Mode II Delamination Toughness from Three- and
Four-Point Bend End-Notched Flexure Tests—c. SCHUECKER AND
B. D. DAVIDSON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
Finite-Element Analysis of Delamination Growth in a Multidirectional Composite ENF
Specimen–M. KONIG, R. KRUGER, AND S. RINDERKNECHT . . . . . . . . . . . . . . . . . . . . . . . 345
Comparison of Designs of CFRP-Sandwich T-Joints for Surface-Effect Ships Based on
Acoustic Emission Analysis from Load TestS–ANDREAS J. BRUNNER AND
ROLF PARADIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
Development of a Test Method for Closed-Cross-Section Composite Laminates
Subjected to Compression Loading–R. B. BUCINELL AND B. ROY . . . . . . . . . . . . . . . 382
Tension Pull-off and Shear Test Methods to Characterize 3-D Textile Reinforced
Bonded Composite T e e – J o i n t s – – s . D. OWENS, R. e. SCHMIDT, AND J. J. DAVIS . . . . . . . 398
STRENGTH PREDICTION
What the Textbooks Won’t Teach You About Interactive Composite Failure
C r i t e r i a – – L . J. HART-SMITH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
Curved Laminated Beams Subjected to Shear Loads, Moments, and Temperature
Changes–s. o. PECK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
Damage, Stiffness Loss, and Failure in Composite S t r u c t u r e s – – s . N. CHAa~rE~EE . . . . . . . 452
Compressive Strength of Production Parts Without Compression
Testing–E. J. BARBERO AND E. A. WEN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 470
ENVIRONMENTAL EFFECTS
Environmental Effects on Bonded Graphite/Bismaleimide Structural
Joints–K. A. LUBKE, L. M. BUTKUS, AND W. S. JOHNSON . . . . . . . . . . . . . . . . . . . . . . . . 493
Accelerated Tests of Environmental Degradation in Composite
Materials–T. G. REYNOLDS AND H. L. McMANUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513
PLENARY SESSION
The Effects of Initial Imperfections on the Buckling of Composite Cylindrical
Shells–J. H. STARNES, JR., M. W. HILBURGER, and M. P. NEMETH . . . . . . . . . .. . . 529
Indexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 551
Overview
The Symposium on “‘Composite Structures: Theory and Practice” sponsored by Committee D-30 on Composite Materials, was held in Seattle on 17th and 18th May 1999. This topic was a departure from the traditional D-30 symposia themes of “Design and Testing” and “Fatigue and Fracture.” The reasons for this were to focus more specifically on structural certification/qualification issues, and to garner more interest and participation from government and industry experts. As stated in the Call for Papers, “‘The objective of this symposium (was) to bring together practitioners and theoreticians in the composite structural mechanics field, to better understand the needs and limitations under which each work.”
The Symposium was structured around seven general topics (the various sessions), seven invited speakers on these or more global issues, the Wayne Stinchcomb Memorial Award and Lecture, and a wrap-up panel discussion with the invited speakers. The following paragraphs provide brief overviews of all of the papers included in this STP. as well as comments on the panel discussion and additional oral presentations given during the Symposium.
Professor Paul Lagace opened the Symposium with an invited talk on “Technology Transition in the World of Composites–An Academic’s Perspective.” Professor Lagace provided the attendees with an insightful and entertaining overview of some of the more popular composite structures research topics over the years, and some of the resulting successes and/or barriers to practical use. No technical publication in this STP was warranted for Prof. Lagace’s editorial subject.
Structural Damage Tolerance
Lincoln USAF/ASC, gave an invited talk and related paper that reviews the development of procedures used by the United States Air Force in the qualification of composite structures. He also reviews Navy programs, and the resulting Joint Service Specification Guide. The challenges in future certification initiatives, in particular, the need to reduce cost and address changes in manufacturing processes are discussed. He proposes a re-examination of the building-block process and a critical review of probabilistic methods.
Dr. [~qrl 3′ Ilcewicz, FAA National Resource Specialist for Composites, gave an invited talk on his previously published “Perspectives on Large Flaw Behavior for Composite Aircraft Structure.'” This presentation gave an authoritative overview of low-velocity impact and discrete source damage threats, certification requirements, and structural response. No technical publication of this work was possible for this STP.
Olsson, Asp, Nilsson, and Sjogren review, in the main work performed at the Aeronautical Research Institute of Sweden (FFA), of studying the effects of impact upon composite structures. Both damage resistance and danrage tolerance are studied, along with an assessment of the effects of global buckling.
Anderson presented a practical approach to design-specific compression strength-after-impact certification. The application cited was that of a carbon/thermoplastic light helicopter tailboom.