An elastic material vibration test apparatus includes a lower support plate having an upper surface on which an elastic material to be tested is placed, an upper support plate disposed above the lower support plate to be spaced apart from the lower support plate, a pillar connecting the lower support plate and the upper support plate, a pressing rod configured to pass through the upper support plate and ascend and descend in a vertical direction, an air bearing installed on the upper support plate and supporting an outer surface of the pressing rod in a non-contact state, a pressing plate coupled to a lower end of the pressing rod to press an upper surface of the elastic material, and one or more weights coupled to the pressing rod above the air bearing.

An impact test apparatus includes a base plate having an upper surface on which a specimen is placed, a collision member that collides with the specimen, a dropping unit that drops the collision member from an upper area of the specimen to the specimen and adjusts a height that the collision member drops, a velocity measurement unit that measures a collision velocity of the collision member when the collision member collides with the specimen, and an evaluation unit that produces a representative value that is a collision velocity at which a probability of breakage of the specimen is about 50%, and evaluates an impact resistance of the specimen based on the representative value.

An elastic material vibration test apparatus includes a lower support plate having an upper surface on which an elastic material to be tested is placed, an upper support plate disposed above the lower support plate to be spaced apart from the lower support plate, a pillar connecting the lower support plate and the upper support plate, a pressing rod configured to pass through the upper support plate and ascend and descend in a vertical direction, an air bearing installed on the upper support plate and supporting an outer surface of the pressing rod in a non-contact state, a pressing plate coupled to a lower end of the pressing rod to press an upper surface of the elastic material, and one or more weights coupled to the pressing rod above the air bearing.

A resonant column device configured to perform a resonant column test on a specimen and measure an angular deformation of the specimen. The resonant column device has a housing mounted on a base, a specimen container within the housing, a cell wall surrounding the specimen container, a load frame within the housing with a support bar above the specimen container, a torque motor suspended from the support bar with a plurality of springs, and a laser deformation sensor within the housing outside of the specimen container. The specimen container is configured to hold the specimen during testing. The cell wall is configured to fluidly isolate the specimen container from an interior volume of the housing. The torque motor is configured to apply a torsional harmonic load to the specimen, and the laser deformation sensor is configured to measure an angular deformation of the specimen.

A racquet including a frame including a head portion, a handle portion, and a throat portion. The head portion is a tubular structure including inner and outer peripheral walls, each having inner and outer surfaces. The head portion of the racquet being formed of a fiber composite material. The fiber composite material includes a plurality of ply arrangements. Each includes a pair of plies defining first and second angles with respect to a composite axis. A section of the outer peripheral wall from the inner surface to the outer surface includes at least three ply arrangements overlaying each other, and the first and second angles of at least two of the at least three ply arrangements being at least 35 degrees. When the racquet is tested under a racquet torsional stability test, the racquet has an angular deflection of less than 5.5 degrees about a longitudinal axis.

An apparatus and method for testing relative hardness of horizontal concrete surfaces includes a weighted platform with scratching pins on a bottom surface of the platform. The pins are arranged in a trapezoidal arrangement. The apparatus is translated over the surface to determine if the surface has reached the desired level of hardness. If translation of the apparatus results in scratching of the surface, the desired level of hardness has not been reached.

An impact test apparatus includes a base plate having an upper surface on which a specimen is placed, a collision member that collides with the specimen, a dropping unit that drops the collision member from an upper area of the specimen to the specimen and adjusts a height that the collision member drops, a velocity measurement unit that measures a collision velocity of the collision member when the collision member collides with the specimen, and an evaluation unit that produces a representative value that is a collision velocity at which a probability of breakage of the specimen is about 50%, and evaluates an impact resistance of the specimen based on the representative value.

An apparatus for testing paving samples includes a base that includes a paving sample tray about the cabinet and configured for translation relative to the cabinet. A roller is configured for imparting compressive forces to a sample carried by the sample tray. An arm is configured for moving the roller from a stowed position to an in-use position where the roller contacts the sample. A cylinder assembly having a piston therein supplies pressure forces to the arm to move the arm from the stowed position to the in-use position, wherein a depth of travel of the arm is limited by the sample. As the sample is compressed, the depth of travel increases. A measurement device is in communication with the cylinder for determining an amount of travel of the arm to thus determine an amount of compression of the sample.

A racquet including a frame including a head portion, a handle portion, and a throat portion. The head portion forms a hoop that defines a string bed plane. The head portion of the racquet being formed of a fiber composite material. When the racquet is tested under a racquet forward/rearward bending test, the racquet has a forward/rearward deflection with respect to the longitudinal axis of at least 8.5 mm when measured in a direction that is perpendicular to the string bed plane and perpendicular to the longitudinal axis. When the racquet is tested under a racquet torsional stability test, the racquet has an angular deflection of less than 5.5 degrees about a longitudinal axis.

A racquet extending along a longitudinal axis and including a frame including a head portion, a handle portion, and a throat portion. The head portion forms a hoop that defines a string bed plane. At least the head portion and the throat portion of the frame are formed at least in part of a fiber composite material. When the racquet is tested under the racquet lateral bending test, the racquet has a lateral deflection of at least 6.0 mm when measured in a direction that is parallel to the string bed plane and perpendicular to the longitudinal axis.