Feltdiameter

Feltdiameter is a dimension used in textile engineering and materials science to characterize felt-based components. It refers, in general terms, to the diameter of a circle that matches the projected area of a felt feature when viewed in a plane. This metric is commonly applied to irregularly shaped felt patches, discs, seals, or other circular or quasi-circular felt elements encountered in manufacturing and assembly.

Calculation of feltdiameter relies on area rather than a physical edge length. If a felt feature has a projected area A in the reference plane, the feltdiameter D is given by D = 2 * sqrt(A / π). For specimens that are already circular discs, the feltdiameter coincides with the actual physical diameter of the disc.

Measurement and estimation methods include planimetric image analysis, digital image processing, or direct measurement with a caliper for simple circular specimens. It is important to specify the reference plane, orientation, and any compression or stacking state, as these factors affect the projected area and thus the feltdiameter.

Applications of feltdiameter include quality control, compatibility checks in assemblies, and quick comparisons between felt components. It can help assess fit for gaskets, spacers, or support pads and may indirectly relate to performance aspects such as coverage, flow resistance, or absorption, though it does not replace direct measurements of thickness, density, or porosity.

Limitations include sensitivity to moisture, compression, and handling, as feltdiameter reflects a projected area, not the intrinsic geometry of the solid felt body. See also diameter, equivalent diameter, planimeter, and image analysis.