Composite laminates

About: Composite laminates is a research topic. Over the lifetime, 10087 publications have been published within this topic receiving 208227 citations.

Some experimental investigations in the drilling of carbon fiber-reinforced plastic (CFRP) composite laminates

Abstract: In this paper, a concept of delamination factor F d (i.e. the ratio of the maximum diameter D max in the damage zone to the hole diameter D ) is proposed to analyze and compare easily the delamination degree in the drilling of carbon fiber-reinforced plastic (CFRP) composite laminates. Experiments were performed to investigate the variations of cutting forces with or without onset of delamination during the drilling operations. The effects of tool geometry and drilling parameters on cutting force variations in CFRP composite materials drilling were also experimentally examined. The experimental results show that the delamination-free drilling processes may be obtained by the proper selections of tool geometry and drilling parameters. The effects of drilling parameters and tool wear on delamination factor are also presented and discussed. Cutting temperature has long been recognized as an important factor influencing the tool wear rate and tool life. An experimental investigation of flank surface temperatures is also presented in this paper. Experimental results indicated that the flank surface temperatures increase with increasing cutting speed but decreasing feed rate. Optimal cutting conditions are proposed to avoid damage from burning during the drilling processes.

Review of z-pinned composite laminates

Abstract: This paper reviews published research into polymer composite laminates reinforced in the through-thickness direction with z-pins. Research into the manufacture, microstructure, delamination resistance, damage tolerance, joint strength and mechanical properties of z-pinned composites is described. Benefits of reinforcing composites with z-pins are assessed, including improvements to the delamination toughness, impact damage resistance, post-impact damage tolerance and through-thickness properties. Improvements to the failure strength of bonded and bearing joints due to z-pinning are also examined. The paper also reviews research into the adverse effects of z-pins on the in-plane mechanical properties, which includes reduced elastic modulus, strength and fatigue performance. Mechanisms responsible for the reduction to the in-plane properties are discussed, and techniques to minimise the adverse effect of z-pins are described. The benefits and drawbacks of z-pinning on the interlaminar toughness, damage tolerance and in-plane mechanical properties are compared against other common types of through-thickness reinforcement for composites, such as 3D weaving and stitching. Gaps in our understanding and unresolved research problems with z-pinned composites are identified to provide a road map for future research into these materials.

Experimental Characterization of Advanced Composite Materials

Abstract: INTRODUCTION Background Laminate Orientation Code Influences of Material Orthotropy on Experimental Characterization Typical Unidirectional Composite Properties References ANALYSIS OF COMPOSITE MATERIALS Constitutive Relations Micromechanics Laminated Plate Theory St. Venant's Principle and End Effects in Composites Lamina Strength Analysis Laminate Strength Analysis Fracture Mechanics Concepts Strength of Composite Laminates Containing Holes References PROCESSING OF COMPOSITE LAMINATES Processing of Thermoset Composites Autoclave Processing of Thermoplastic Composites Determination of Volume Fractions of Fibers, Resin and Voids References TEST SPECIMEN PREPARATION, TEST EQUIPMENT, STRAIN AND DEFORMATION MEASUREMENTS Cutting the Composite Laminate Tabbing Materials Tab Bonding Suggested Tab Bonding Procedures Hinge Attachment for DCB and MMB Specimens Specimen Conditioning Strain and Displacement Measurements Testing Machines References LAMINA TENSILE RESPONSE The Need for Lamina Testing Introduction to Tensile Testing Primary Concerns Specimen Configurations and Test Procedures Data Reduction References LAMINA COMPRESSIVE RESPONSE Shear-Loading Test Methods End-Loading Test Methods Combined Loading Compression (CLC) Test Methods Compression Test Procedures Failure Modes General Data Reduction Backing out Unidirectional Lamina Strength from a Test of a Cross-Ply Laminate Summary of Compression Test Methods References LAMINA SHEAR RESPONSE Iosipescu Shear Test Method (ASTM D 5379) Two-Rail Shear Test Method (ASTM D 4255) Three-Rail Shear Test Method (ASTM D 4255) [+-45]ns Tension Shear Test Method (ASTM D 3518) Short Beam Shear Test Method (ASTM D 2344) Summary References LAMINA FLEXURAL RESPONSE Testing Configuration Three-Versus Four-Point Loading Specimen Preparation and Flexural Test Procedures Data Reduction References LAMINA OFF-AXIS TENSILE RESPONSE Deformation and Stress in Unconstrained Specimens Influence of End Constraint Off-Axis Tensile Strength Test Procedure Data Reduction References LAMINA THERMOELASTIC RESPONSE Temperature Gage Sensing System Temperature Compensation Measurement of Thermal Expansion Data Reduction References LAMINATE MECHANICAL RESPONSE Data Reduction for Stiffness Properties Laminate Strength Analysis Test Specimen Preparation Test Procedures Data Reduction Example of a Typical Analysis: Axial Tensile Response of a Laminate References LAMINATE THERMOELASTIC RESPONSE Preparation of Test Specimens and Measurement of Thermal Expansion Data Reduction Analysis of Thermoelastic Response References OPEN-HOLE TENSILE AND COMPRESSIVE STRENGTHS OF LAMINATES Point and Average Stress Criteria Test Specimen Preparation Tensile Test Procedure and Data Reduction Standardized Open-Hole Tension Test Method Standardized Open-Hole Compression Test Methods References CHARACTERIZATION OF DELAMINATION FAILURE Double Cantilever Beam (DCB) Test End-Notched Flexure (ENF) Test Four-Point Bend ENF (4ENF) Test Mixed-Mode Bending (MMB) Test Edge-Cracked Torsion (ECT) Test References Appendix A: Compliance and Stiffness Transformations and Matrix Operations Appendix B: Preparation of Panels and Test Specimens Appendix C: Sample Laboratory Report Appendix D: Unit Conversions Index