UNE-EN ISO 14126:2024

1.1 This document specifies methods for determining the compressive properties, in directions parallel to the plane of lamination, of fibre-reinforced plastic composites, based on thermosetting or thermoplastic matrices. The compressive properties are of interest for specifications and qualitycontrol purposes. The test specimens are machined from a flat test plate, or from suitable finished or semi-finished products

1.2 Three loading methods and two types of specimen are described.

The loading methods are:

Method 1: provides shear loading of the specimen (gauge length unsupported)

Method 2: provides combined loading of the specimen (gauge length unsupported)

Method 3: provides end-loading of a plain specimen (i.e. no tabs) (gauge length unsupported)

NOTE 1 For tabbed specimens loaded using method 2, load is transferred through a combination of endloading and shear-loading through the tabs.

NOTE 2 End-loading of un-tabbed specimens is used only for modulus measurement.

The specimen designs are:

Type A specimen: rectangular cross-section, fixed thickness, end-tabbed (mainly for aerospace style preimpregnates (~ 0,125 mm ply thickness)

Type B specimen: rectangular cross-section, range of thicknesses, untabbed or end-tabbed, two specimen sizes are available (B1and B2).

The type A specimen is the preferred specimen for unidirectionally or biaxially reinforced materials tested in the fibre direction, where the fibres are normally either aligned continuous or aligned long (>7,5 mm) discontinuous. The B1 and B2 specimen are preferred for multi-directional aligned; mat, fabric and other multi-directionally reinforced materials where the fibre structure is more complex and/or coarser.

1.3 Criteria are given for checking that the combination of test method and specimen design result in valid failures. It is noted that alternative test method/specimen combinations will not necessarily give the same result.

1.4 The methods specify required dimensions for the specimen. Tests carried out on specimens of other dimensions, or on specimens that are prepared under different conditions, may produce results that are not comparable. Other factors, such as the speed of testing, the support fixture used and the conditioning of the specimens, can influence the results. Consequently, when comparative data are required, these factors must be carefully controlled and recorded.

1.5 Fibre-reinforced plastics are usually anisotropic. It is therefore often useful or required to prepare test specimens in at least the two main orthogonal directions (in the plane) of anisotropy (see Figure 1), or in directions previously specified (for example a lengthwise direction associated with the production process).

NOTE Examples of tests required to be undertaken at different orientations (i.e. 0° and 90°) in the test plateare given in ISO 10350-2 and ISO 20144 (see bibliography).