A tennis racquet extending along the longitudinal axis and capable of being tested under a forward/rearward bending test and a torsional stability test includes a frame having a head portion, a handle portion, and a throat portion positioned between the head portion and the handle portion. The head portion forms a hoop that defines a string bed plane. At least the head portion and the throat portion of the racquet are formed at least in part of a fiber composite material. The throat portion includes a pair of throat elements. When the racquet is tested under the forward/rearward bending test, the racquet has a forward/rearward deflection with respect to the longitudinal axis of at least 9.0 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 the torsional stability test, the racquet has an angular deflection of less than 5.5 degrees about the longitudinal axis.

A racquet includes a frame extending along a longitudinal axis. The frame includes head and handle portions, and a throat portion positioned between the head and handle portions. The head and throat portions are formed at least in part of a fiber composite material. The material includes a plurality of ply arrangements. Each of the arrangements includes one ply having a first plurality of fibers defining a first angle with respect to a composite axis, and another ply having a second plurality of fibers defining a second angle with respect to the composite axis. The first and second angles are substantially the same except the angles have opposite polarities with respect to the composite axis. The head portion includes at least three arrangements overlaying each other, and the first and second angles of at least two of the at least three arrangements are at least 35 degrees.

A sports racquet capable of being tested under a racquet vibration test, and including a frame extending along a longitudinal axis. The frame includes a head portion, a handle portion, and a throat portion positioned between the head portion and the handle portion. The head portion forms a hoop that defines a string bed plane. The throat portion includes a pair of throat elements. At least the head portion and the throat portion of the racquet are formed at least in part of a fiber composite material. The head portion including a forward hoop surface and a rearward hoop surface. The distance between the forward and rearward hoop surfaces defines a beam height distance. The head portion has a maximum beam height distance of at least 19 mm. When the racquet is tested under the racquet vibration test, the racquet has a vibration of no greater than 130 Hz.

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.

A test result evaluating method and a material tester are provided. A test result evaluating part includes a representative value calculating part that acquires a representative value of section data corresponding to one period of a natural vibration frequency from data of a time period representing a force applied to a test piece also including a natural vibration and a ratio calculating part that calculates a ratio between the representative value acquired by the representative value calculating part and a value based on an amplitude of the natural vibration. The representative value calculating part and the ratio calculating part are arranged in a test result evaluating part as programs realizing functions by operating an arithmetic operation device.

Embodiments relate to an apparatus and method for determining the complex shear modulus of compliant viscoelastic specimens. The apparatus comprises at least one magnet configured to provide a magnetic field; a specimen and a motor secured to the end of the specimen, wherein the motor is positioned proximate to the magnet such that the motor is in the magnetic field; a first coil fixed to the motor; an amplifier configured to provide a current in the first coil, such that the first coil interacts with the magnetic field and the current to apply a force to the specimen; a second coil fixed to the motor and configured to measure voltage; a mirror secured to the motor; a laser source focused on the mirror and configured to produce a laser, such that the mirror reflects the laser; and a photodetector configured to detect the laser reflected from the mirror.

A tennis racquet extending along a longitudinal axis and capable of being tested under a lateral bending test and a forward/rearward bending test, includes a frame having a head portion, a handle portion, and a throat portion positioned between the head and handle portions. The head portion forms a hoop that defines a string bed plane. At least the head portion and the throat portion of the racquet are formed at least in part of a fiber composite material. The throat portion includes a pair of throat elements. When the racquet is tested under the lateral bending test, the racquet has a lateral deflection of at least 6.0 mm when measured in a direction parallel to the string bed plane and perpendicular to the longitudinal axis.

Ice test devices include an ice adhesion test device. The ice adhesion test device comprises an ice adhesion test target in the form of a well in which, in use, a layer of accreted ice is built up. The target comprises a sample plate at the bottom of the well and an ice-engagement element positioned circumferentially around the sample plate and providing a side wall of the well, and wherein the sample plate is rotatable relative to the ice-engagement element. The ice adhesion test device also comprises torque means for applying a rotational torque between the sample plate and the ice-engagement element. The ice adhesion test device also comprises transducer means for, at least at a point at which the layer of accreted ice separates from the sample plate, measuring the rotational torque and/or the stress on the ice.

The present invention refers to an equipment that allows the performance of fatigue testing at ultrasonic frequencies in a multiaxial loading, more specifically biaxial. The equipment is formed by two components, the horn (1) and the specimen (5), which are coupled with each other. The horn (1) and the specimen (5) possess such geometry that their resonant frequency which, is relevant for the testing, is synchronized with the excitation frequency of the exciter, so that the whole equipment vibrates in free regime. Through its vibration mode, the horn (1) transforms the pure axial cyclic movement which it receives from the exciter into a mixed movement comprised of axial and torsional cyclic and in-phase movements. The specimen (5) possesses, synchronized at the same frequency, its first axial vibration mode and its third torsional vibration mode.