Experimental and Applied Mechanics

Extracting Crack-tip Field Parameters in Anisotropic Elastic Solids From Full-field Measurements Using Least-squares Method and Conservation Integrals (Experimental and Applied Mechanics) Part 1

ABSTRACT: This paper presents parameter-estimation methods developed to determine crack-tip field parameters in anisotropic elastic solids from full-field experimental data. The crack-tip field parameters of interest include not only stress intensity factors but also effective crack-tip positions. Two approaches that are based on least-squares method and conservation integrals were presented. In the approach based on […]

Extracting Crack-tip Field Parameters in Anisotropic Elastic Solids From Full-field Measurements Using Least-squares Method and Conservation Integrals (Experimental and Applied Mechanics) Part 2

EXPERIMENT Experiment procedure The composite material investigated in this study is Cyply 1002, a glass-fiber reinforced epoxy laminate, manufactured by Cytec Engineered Materials. A cured composite panel of that has 0/90 cross-ply laminates are used. Each composite panel has 13 plies of 3.3mm thickness. The composite laminate has 13 plies in the arrangement of cross-ply […]

Velocity Measuring Approaches for the Determination of Ballistic Limits of GLARE 5 Fiber-Metal Laminate Plates (Experimental and Applied Mechanics)

ABSTRACT In this study, 152.4 mm by 101.6 mm (6"*4") GLARE 5 plates with various thicknesses were impacted by a 0.22 caliber bullet-shaped projectile using a high-speed gas gun. Velocities of the projectile along the ballistic trajectory were measured at different locations throughout the test using (1) a pair of laser-beam optoelectronic paths near the […]

Underwater Explosive Loading of Curved Composite Plates: Experimental and Computational Comparisons (Experimental and Applied Mechanics)

ABSTRACT The effect of underwater shock loading on an E-Glass / Vinyl-Ester composite material has been studied. The work consists of experimental testing, utilizing a water filled conical shock tube and computational simulations, utilizing the commercially available LS-DYNA finite element code. The plates consist of elliptically curved geometry with 0/90 biaxial laminates. The plates are […]

Adhesion Strength in Metal/Polymer Composites (Experimental and Applied Mechanics)

ABSTRACT A load applied to a composite is transferred from the matrix to the dispersed phase through their shared interface. The performance of the composite depends strongly on the interfacial adhesion between the constituents. Shear strength, resistance to delamination, and effective load transfer between the matrix and the inclusion are improved when the interfacial bond […]

Modal-Parameter Identification From Nonstationary Ambient Vibration Data (Experimental and Applied Mechanics) Part 1

ABSTRACT Identification of modal parameters from response data only is studied for structural systems under nonstationary ambient vibration. By assuming the ambient excitation to be nonstationary white noise in the form of a product model, the modal parameters of a system could be identified through the correlation method in conjunction with a technique of curve-fitting. […]

Modal-Parameter Identification From Nonstationary Ambient Vibration Data (Experimental and Applied Mechanics) Part 2

ITD Extraction In the following, we will extend the ITD method to identify modal parameters of a structure from forced-response data. Recall that in the conventional ITD analysis, which uses free-decay responses of a structure to identify its modal parameters in complex form [4], we define a system matrix A , such that where Y […]

High-Speed Digital Image Correlation Measurements of Random Nonlinear Dynamic Response (Experimental and Applied Mechanics) Part 1

ABSTRACT Future United States Air Force (USAF) high-speed vehicles will require innovative, non-contacting full-field measurement techniques to validate analysis and design practices. In this experimental investigation, the authors explore the feasibility of using high-speed 3D digital image correlation (DIC) to measure the geometrically nonlinear and stochastic response of a compliant panel representing thin-gauge aircraft-like structure. […]

High-Speed Digital Image Correlation Measurements of Random Nonlinear Dynamic Response (Experimental and Applied Mechanics) Part 2

TEST RESULTS The preliminary compliant panel tests in the RC-19 wind tunnel used only the strain gage and the single vibrometer point to monitor and record panel response. The lack of spatial resolution this created, combined with the varying temperature difference between the frame and panel and little-understood dynamic pressure across the face of the […]

Experimental Modal Analysis of an Inflatable, Self-rigidizing Toroidal Satellite Component (Experimental and Applied Mechanics) Part 1

ABSTRACT Modal testing of an extremely flexible self-rigidizing inflatable torus with regular pattern of hexagonal domes was carried out. For the first time the feasibility of using a non-contact in-house fabricated electromagnetic excitation in modal testing of such an ultra-flexible inflatable structure was investigated. Non-contact transducers, laser displacement sensors, were used in this study. Non-contact […]

← Previous Entries

Next Entries →