Gm Global Technolgoy Operations, Inc.

Delco Electronics Corporation

Cameron John Dasch

Daniel H Hopper

Robert L Alig

Norman Dale Brinkman

Lynn A Rockwell

On a friction stir spot welded workpiece having a first side including a friction stir spot weld hole and an opposing smooth second side, an eddy current probe is passed over the spot weld hole from the second side, and an eddy current signal representative of a material thickness of the workpiece is produced. The eddy current is analyzed via an eddy current analyzer, and a graphic representation of the analyzed eddy current signal is monitored as the probe passes over the spot weld hole, and a local minima of the graphic representation defined by a displayed characteristic J-shaped curve is identified, the local minima defining a remaining material thickness of the workpiece at the bottom of the spot weld hole. From the graphic representation, a value of the remaining material thickness is determined, and a weld strength of the spot weld as a function of the remaining material thickness is determined.

Method and apparatus for analyzing weld strength of friction stir spot welds

The present invention provides an ultrasonic inspection assembly having an ultrasonic transducer mounted on a stage, with a support structure below. The support structure is coupled to the stage, and the support structure has an interior space filled with a couplant media. The transducer is oriented such that it transmits ultrasonic waves through the media. A drive mechanism rotates one of the stage and the support structure relative to the other one of the stage and the support structure.

Cylindrically-rotating ultrasonic phased array inspection method for resistance spot welds

A method is provided for forming a composite material and article using nanometer-size vapor grown carbon fibers. The preferred carbon fibers are characterized by diameters of substantially less than about one micrometer, and more typically less than about 0.2 micrometers, and are of the type formed by a continuous gas phase reaction. The polymeric matrix of the composite material is formed from a thermoplastic resin having a surface tension which is sufficiently low, so as to promote wetting of the surfaces of the nanometer-size carbon fibers. The thermoplastic resin is mixed with the carbon fibers and a solvent so as to granularize the mixture and thereby facilitate subsequent handling and mixing of the carbon fibers. Final mixing occurs at temperatures near the melting point of the thermoplastic resin and for a duration which is sufficient to ensure that the carbon fibers are adequately wetted by the thermoplastic resin, so as to provide adhesion between the fibers and the thermoplastic. The composite material is characterized by improved strength and stiffness.

Composite of small carbon fibers and thermoplastics and method for

A method and apparatus for enhancing the cold starting performance of a spark ignition, internal combustion engine fueled with an alcohol-based fuel mixture is described. The quantity of fuel mixture delivered to the engine is regulated to establish a combustible fuel vapor-air mixture in each engine cylinder during cranking, while restricting the accumulation of unvaporized fuel in the each cylinder so as not to exceed a predetermined amount. In addition, each cylinder spark plug is provided with an ignition current having a peak magnitude sufficient to achieve voltage break down across each spark plug arc gap, when each gap is resistively loaded due to wetting in accordance with the predetermined amount of accumulated unvaporized fuel. Preferably, the quantity of fuel delivered to the engine during cranking is reduced at a substantially exponential rate as a function of the cumulative number of revolutions the engine is rotated during cranking. An ignition coil having a secondary to primary winding turns ratio in the order of 65:1, with its secondary winding wrapped onto a plurality of partitions in a segmented dielectric bobbin, is employed to provide the required ignition current for firing the engine spark plugs when the predetermined amount of unvaporized fuel accumulates in the engine cylinders.

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Bloomfield Hills, MI, United States of America

Cameron John Dasch