A method for inspecting a joining surface (14) of a substrate, wherein a component is to be adhered to the joining surface of the substrate by means of an adhesive material (27), wherein the method comprises the following steps: providing at least one planar test textile (20), which has a fiber material (21) and an adhesive primer (22), applying the planar test textile to at least one part of the joining surface of the substrate to which the component is to be adhered so that the adhesive primer of the planar test textile contacts the joining surface of the substrate, at least partially curing the adhesive primer of the planar test textile in order to integrally bond the planar test textile to the substrate by means of the adhesive primer, pulling off the planar test textile after at least partially curing the adhesive primer and inspecting the joining surface by means of a qualitative evaluation of the fracture pattern between the cured adhesive primer and the planar test textile and/or by means of a quantitative evaluation of the pull-off force determined when pulling off the planar test textile.

In one version there is provided a test system including a layup tool having a layup surface, and two fairing bars attached to the layup surface. The test system includes the composite laminate having a plurality of stacked plies, and positioned between the two fairing bars. The test system includes fiber distortion initiator(s) positioned at one or more locations under, and adjacent to, one or more plies of the plurality of stacked plies. The test system includes two caul plates with a gap in between, and positioned over the composite laminate. When the test system undergoes a pressurized cure process with a vacuum compaction, a restricted outward expansion of the plurality of stacked plies by the fairing bars, and a pressure differential region formed by the one or more fiber distortion initiators at the one or more locations, create the controlled and repeatable out-of-plane fiber distortion in the composite laminate.

The present disclosure provides a 3-dimensional filamentous fiber matrix, systems comprising the matrix, and methods for using the matrix and the systems.

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 rig for testing mode II fatigue of a composite component. The rig includes a clamp for clamping one end of the component. A first contact arrangement is provided for contacting one side of the component and a second contact arrangement is provided for contacting an opposing side of the component, the first and second contact arrangements being spaced from the clamp. A loading fork is provided for applying load to the component. The loading fork includes a first and a second portion arranged such that in use, when the loading fork is loading the component in one direction the first portion contacts the first contact arrangement and the second portion is spaced from the second contact arrangement, and when the loading fork is loading the component in an opposite direction the first portion is spaced from the first contact arrangement and the second portion contacts the second contact arrangement.

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 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.