Abstract: A fatigue testing apparatus (10) for simultaneously subjecting a plurality of material test specimens (24) to cyclical tension loading to determine the fatigue strength of the material. The fatigue testing apparatus includes a pulling head (12) having cylinders (26) defined therein which carry reciprocating pistons (32). The reciprocation of the pistons is determined by cyclical supplies of pressurized fluid to the cylinders. Piston rods (18) extend from the pistons through the pulling head and are attachable to one end of test specimens, the other end of the test specimens being attachable to a fixed base (38), causing test specimens attached between the piston rods and the base to be subjected to cyclical tension loading. Because all of the cylinders share a common pressurized fluid supply, the breaking of a test specimen does not substantially affect the pressure of the fluid supplied to the other cylinders nor the tension applied to the other test specimens.

Abstract: The invention is a method of determining whether an adhesively bonded joint between two structural elements meets established strength requirements. The method comprises the following steps: (1) Determining by test the levels of acoustic energy to be directed and/or focused by a transducer 12 on a minute area of the adhesively bonded joint 14 and further the application times thereof.

Abstract: A method of image display of a specimen by an ultrasonic wave microscope comprising an acoustic wave propagating medium, a piezoelectric member provided at one end of said medium for generating an ultrasonic beam, and an acoustic wave lens formed at an opposite end of said acoustic wave propagating medium and having a predetermined focal point, said method comprising the steps of two-dimensionally scanning a specimen disposed substantially at said focal point by said ultrasonic beam while moving one of said specimen and said beam relative to the other, and applied to said specimen repetitive stress selectively during the scanning of said specimen.

Abstract: A fatigue damage indicator includes a thin plate mounted between or integral with two members to which a stress is to be applied, the disposition of the two members being such that the thin plate is stressed in shear.Slots extending in the direction of the applied stress may be provided to ensure that cracks formed by fatigue stress propagate in a desired direction and the crack propagation is designed to ensure that a part of the plate becomes detached or is bent substantially away.

Abstract: A closed system, impact-fatigue test machine for grinding balls comprised of a vertically extending guide member and a lift conveyor wherein the guide member lies above a recessed anvil and defines in its center a longitudinal opening. Each grinding ball is carried upwardly by the conveyor to an opening in the upper portion of the guide member and then is dropped into the guide member to land laterally supported, upon an earlier dropped grinding ball which rests on the anvil below. The earlier dropped ball is then pushed from the anvil toward the conveyor causing the dropped ball to impact the anvil below. The number of dropping cycles that each ball can tolerate without fracture is counted by a counter. Fracture of the balls is detected by a fracture detector.

Abstract: A fatigue detector for detecting potential fatigue failure of a bolster and/or side frames of a railway car truck. The fatigue detector comprises one or more redundant designed members located in areas of critical stress loadings of the truck, wherein the fatigue detectors are structured to fail under a stress loading less than that causing the failure of the bolster and/or side frames in which they are located. The fatigue detector is located in an opening so as to be easily inspected visually to determine its condition and particularly whether or not it has failed.

Abstract: An improved apparatus and process are described for measuring linear and non-linear viscoelastic properties of viscoelastic materials such as nylon, polyester tire cord, rubber, rubber-tire cord composites and the like. The properties are determined by subjecting a sample material to a constant-rate strain displacement having a small amplitude high frequency sinusoidal strain displacement superimposed thereon, and analyzing the overall resulting material stress. The obtained properties can be used to predict and estimate actual end use characteristics of the material such as longevity and mechanical loss during performance. In the case of tire cord, this latter characteristic can be surprisingly related to efficiency of fuel consumption in automotive vehicles.

Abstract: An indicator for recording the load at which a fatigue specimen breaks during the last cycle of a fatigue test. A load cell is attached to the specimen which is alternately subjected to tension and compression loads. The output of the load cell which is proportional to the load on the specimen is applied to the input of a peak detector. Each time that the specimen is subjected to a compression load, means are provided for appyling a positive voltage to the reset of the peak detector to reset it. Hence, during the last cycle of the tension load the peak detector measures the maximum load on the specimen. Means are also provided for disconnecting the load cell from the peak detector when there is a failure in the specimen.