Acquisition of a full field non-contact 3D DIC System for charaterizing crack propagation under variable amplitude loading
Abstract
Project Summary: Acquisition of a full field non-contact 3D-DIC system for characterizing crack propagation in naval and aerospace structuresRequested EquipmentThis proposal requests funds to support the acquisition of a full field non-contact three-dimensional (3D) digital image correlation (DIC) system in support of DoD-funded research at the Bert Cooper Engineering Laboratory (BCEL) of Oklahoma State University (OSU). The system will be mainly used to support experimental and numerical research focusing on characterizing crack propagation in naval and aerospace structures and designing maintenance and repair procedures for extending the service life of these structures in the presence of fatigue damage. The DIC system includes stereo vision cameras, data acquisition box, and image acquisition and processing software, in addition to essential hardware such as a workstation, tripods, and several lenses to support a wide range of characteristics of the field of view. Calibration targets are also included in the system to enable the 3D image correlation. The system will be mainly used for 3D surface profiling, measuring 3D displacements and rotations, and real-time tracking of 3D strains.Related Research ActivitiesThis request supports multiple experimental research endeavors at the BCEL to assess the structural behavior of naval and aerospace structures. Among these endeavors is a currently funded effort to characterize crack propagation in naval structures under variable amplitude loading. This current research includes testing small-scale coupons and large-scale stiffened box girders. The DIC system will provide unsurpassed capability to (a) measure the crack opening displacement in small-scale middle tension coupons, (b) characterize the strains around the crack tip, (c) measure the crack size, (d) validate the numerical models, and (d) develop non-destructive techniques to measure the residual stresses occurring during the large-scale specimen welding and fabrication, among others. Many of these tasks are not possible with the application of traditional sensors such as strain gages, linear variable differential transformers (LVDTs), and crack clip gages. The acquisition of the system will significantly improve the research capabilities of the BCEL and enable it to support future DoD-related research needs in fatigue assessment of naval and aerospace components.Related Educational ActivitiesThe requested equipment will be integrated into the laboratory demonstration activities of several undergraduate and graduate level classes currently taught by the principal investigator. These classes include structural analysis, advanced mechanics of materials, structural steel design, steel plastic design, and structural dynamics. The requested system will be used to construct laboratory activities intended to help the students better understand the concepts covered in class through visualizing variations of strains and displacements within a body. These concepts include simple phenomena such as the normal and shear strain distribution within bodies under flexural and torsional loading, as well as more advanced topics such as shear lag in steel structures and stress concentrations around notches and holes.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 19, 2020
- Source ID
- N000142012860
Entities
People
- Mohamed Soliman
Organizations
- Office of Naval Research
- Oklahoma State University–Stillwater
- United States Navy