Presently, the most commonly used tests to assess the structural integrity of particleboard are the boil swell and the cyclic soak tests. Although these tests predict how well the particleboard will perform, with the exception of visual examination, there are at present no nondestructive evaluation (NDE) techniques for its structural integrity. The purpose of this study is to investigate the applicability of the acousto-ultrasonic technique to assess the functional structural integrity of particleboard. During the pressing operation, wood-based composite materials are compressed in thickness beyond the gross density of the wood species and remain compressed because of resin bonding.

Failure of rope can result in significant property damage and/or personal injury. Because ropes can fail with no quantifiable change in visual appearance, the development of nondestructive testing evaluation techniques is essential in improving the safety and reliability of operations involving rope. The purpose of this study is to investigate the applicability of the acousto-ultrasonic stress wave factor technique to the nondestructive evaluation of nylon and kevlar ropes.

A nondestructive technique to evaluate the strength of wood in early stages of decay is being investigated. Al though the ``pick test'' is commonly used to detect wood decay in the field, it has not been known how advanced decay must be before it can be detected by this means. Because much of the wood's strength is lost in the early stages of decay, a high-sensitivity testing procedure is desirable. The importance of this research can be appreciated by noting that for each real estate transaction only a termite inspection is required even though the wood frame structure may have reached moderate or advanced stages of decay.

Concrete is unusual among construction materials in that it is manufactured as used and cannot be tested for acceptance in advance. Acceptance is commonly based on strength tests at an advanced age. Clearly, a need exists to assess the quality of concrete much earlier, ideally before it is placed. It is generally agreed that the most important parameter for determining the quality of concrete is the water-cement ratio. The objective of this study is to investigate a procedure for the instantaneous determination of water-cement ratio to allow a go/no go decision on an actual batch prior to discharge.

Laminated safety glass is widely used in architectural applications and in windshields of motor vehicles. The purpose of this study is to nondestructively evaluate the adhesive bond strength between the plastic interlayer and the two adjacent glass plates in laminated safety glass.

To prevent corrosion, steel tanks are sometimes protected with a layer of coating material. When a delamination between the coating layer and the steel substructure occurs, a void is initiated. Because water will find its way to these voids, corrosion will usually start at these delaminated areas. The purpose of this study is to investigate the feasibility of using the acousto-ultrasonic nondestructive evaluation technique to detect and evaluate the adhesive bond strength (delaminations in particular) between the coating layers and the steel substructure. Specimens with areas without any damage, areas with visible delaminations, and areas without visible delaminations but with possible damage (i.e., reduction of adhesive bond strength) are studied.

Friction welds are currently used in plastic components of air intake manifolds. The evaluation/characterization of the weld (weld defects as well as the strength) is important for the structural integrity of this component. The purpose of this project is to develop a robust nondestructive testing and evaluation method to evaluate/characterize friction welds in plastic components. Both the ultrasonic immersion C-scan method and the acousto-ultrasonic approach will be used to evaluate/characterize friction welds.

The structural integrity (i.e., mechanical properties) of spot welds is clearly dependent upon the amount of diffusion between the two metals in contact during the welding process. Currently, the principal investigator does not know of any nondestructive testing and evaluation technology capable of evaluating the fitness for service of spot welds. Traditional ultrasonic approaches based upon the pulse-echo and pitch-catch techniques are unable to evaluate the strength of these connections. The purpose of this project is to develop a new technique based upon the acousto-ultrasonic approach to nondestructively evaluate the fit- ness for service (i.e., structural integrity) of spot welded connections.

Underinflated or run-flat radial truck tires can be subjected to steel cord fatigue damage caused by overflexing of the tire. Weakened cords may break with potential catastrophic consequences such as loss of life. The purpose of this project is to develop a prototype instrument capable of 100% on-line inspection of new or retreaded tires. The instrument should provide easily interpreted results (color-coded scans) to reduce the possibility of operator error.

Using impulse-echo (IE), spectral analysis of surface wave (SASW), pulse velocity (PV), and acousto-ultrasonics (AU), the purpose of this project is to develop an instrument capable of scanning airport pavements to evaluate layer thicknesses, material properties, and defects such as damage accumulation and delaminations. The output of this instrument should include a color-coded feature pavement scan.