Nondestructive Evaluation Laboratory

Overview

The Federal Highway Administration’s (FHWA’s) Nondestructive Evaluation (NDE) Laboratory is the keystone of FHWA’s research and testing efforts related to the application of nondestructive testing technologies for assessment of highway infrastructure. The mission of the NDE Laboratory is:

…to conduct state-of-the-art research and testing of nondestructive testing systems and technologies to improve the Nation’s highway infrastructure.

The laboratory is designed to act as a resource for State transportation agencies, industry, and academia concerned with the development and testing of innovative NDE technologies. The laboratory provides independent evaluation of NDE technologies, develops new NDE technologies, and provides technical assistance to States exploring the use of these advanced technologies. The NDE Laboratory utilizes a series of unique resources to evaluate and assess the factors affecting the reliability and performance of NDE systems.

NDE Laboratory Facilities

The NDE Laboratory provides a facility for the development and testing of NDE technologies. The technologies researched at the NDE Laboratory include conventional/phased array ultrasonics, conventional/advanced eddy current, acoustic emission, ground penetrating radar, infrared thermography, and impact echo. The NDE Laboratory also includes an 11.8 m (meter) by 3.6 m structural loading floor used to construct scaled models to represent field conditions and/or use actual bridge elements or specimens to conduct research and testing. In addition to functioning as a staging area for research conducted at test bridges, the laboratory space is equipped with storage and test setup areas.

Specimen Library

An extensive collection of component specimens is an important part of the NDE Laboratory. Component specimens are small sections of highway structures (both with and without defects) that have been removed from inservice bridges or that are manufactured to precise measurements. The collection of component specimens is continually evolving as specimens become available from decommissioned bridges, are purchased from qualified vendors, or are manufactured in the NDE Laboratory.

In addition to a variety of specimens, this collection includes specimens with different configurations in steel bridges. These specimens have different features of joint geometries, material thicknesses, coatings, and weld defects. The inventory includes a number of butt-weld specimens with complete joint penetration (CJP) groove welds, butt-welds with well-bonded bridge coatings, T-joint specimens with fillet weld butt joints, and reentrant corner joint specimens with fillet welds. Engineered cracks are embedded in these specimens and a variety of crack geometries are represented.

NDE Laboratory’s Computer Lab

The computing capability of the NDE Laboratory consists of two individual units (computing boxes) clustered together. Each box has 8 dual processors (or 16 cores). Accordingly, the two-unit cluster is a parallel facility with 32 cores. These parallel computers are connected through the Internet II national network to the cluster supercomputer (1024 CPUs) in the Transportation Research and Analysis Computing Center (TRACC) located in the Argonne National Laboratory (ANL). The computing machine is loaded with a massive parallel processing (MPP) version of a finite element program called LS-DYNA and FEMAP by UGS for finite element modeling, analysis, and simulation of complex real world problems. Research using these computing facilities has been focused on advanced computing and large scale dynamics simulation of highway bridges. The work includes large bridge model dynamic response analyses, simulations of traffic flow loads, wind-rain loads for cable-stayed bridges, meshless computation for crack detections in highway structures, nonlinear dynamics simulations for chaos control of cable-stayed bridge vibrations, as well as data analyses covering a wide range of advanced NDE tasks.

Equipment

The NDE laboratory includes state-of-the-art NDE equipment, such as advanced phased array ultrasonic flaw detectors used for detection and sizing of surface and sub-surface flaws in metals. The laboratory contains conventional and advanced eddy current systems that are capable of detecting and sizing surface flaws in metals.

An acoustic emission data acquisition system with a flexible sensor fusion interface for input and processing of a variety of sensors is also available. The system is capable of operating in both extreme weather and laboratory conditions; can be used to monitor cracks; and has the ability to transmit data wirelessly to a remote location. The system uses the software package for acoustic emission data collection, various types of data/graphs analysis, and surveillance monitoring.

The ground penetrating radar system in the laboratory takes advantage of synthetic aperture radar techniques that capture a series of radar waveform responses at regularly spaced intervals. The laboratory also has infrared thermography testing capabilities. The infrared (IR) camera has thermal fusion functionality that allows for easier identification and interpretation of infrared images.

The laboratory is equipped with a 22-kip load frame with an environmental testing chamber. The environmental chamber enables the mechanical testing of materials and components across a broad range of temperature, humidity, and caustic conditions. They are ideal for conducting tension, compression, bend, and cyclic fatigue testing of metals, composites, and ceramics.

An X–ray computed tomography (CT) and digital radiography imaging system were built to accommodate the research needs of the laboratory. The system can benefit many industrial and scientific applications, including materials research, nondestructive testing, core sample characterization, weld inspection, failure analysis, and reverse engineering. The system has been used by researchers at the NDE Laboratory for various projects such as determination of air void parameters, crack propagation, and internal structure characterization of portland cement concrete and asphalt concrete structures.

Publications

NDE Showcase for Bridge Inspectors, Sep 2009

Laboratory and Field Testing of Automated Ultrasonic Testing (AUT) Systems for Steel Highway Bridges, FHWA HRT–04–124, April 2005

Guidelines for Ultrasonic Inspection of Hanger Pins, FHWA–HRT–04–042, July 2004

Techbrief: Reliability of Visual Inspection for Highway Bridges Volume I: Final Report and Volume II: Appendices (FHWA–RD–01–020 and–021)

• Volume I: Final Report (FHWA–RD–01–020, June 2001)
  
  
• Volume II: Appendices (FHWA–RD–1–021, June 2001)