Bend testing

Bend testing with plastics (DIN EN ISO 178)

For the characterization of material specific properties of plastics the bend testing amongst others is used. Normally test pieces are produced out of the materials, which should be tested in the injection molding and are tested according to DIN 178 with a 3 point- or 4 point picture. Alternatively test pieces with an appropriate size can be taken from finished parts.

DIN EN ISO 178

Bend testing with metals

Bending experiments with metals are performed for the determination of the bending strength and the maximum bending in case of fracture. For this quasi-static experiment the bending over the traverse way is measured and the bending angle at the first crack determined.

The test procedure is illustrated with a tension-extension-graph. Additionally there is the possibility to capture the experiment with a video camera. Hereby a stamp is pressing centered and parallel to the bearings on the test object.

The average bearing distance is standard-compliant or individually adjusted for the experiment. The bearing radius can come to R2 or R5. Commonly 3-point bend tests are performed.

At the 4-point bend test the charge is produced by a double stamp. By this the force is produced without additional shear forces, what leads to a constant bending moment between the bearing points.

Bend testing with composite materials

For the statistic characterization of fiber-reinforced plastics we offer next to tensile tests also 3- and 4-point-bend tests. At the 3-point bend test the deflection is determined by the traversal pick-up.

The advantage of the 4-point bend test is the shear force free area between the force application points of the double stamp. The deflection is determined with a direct measurement in the middle of the sample between the bearings. Hereby an extensometer with an accuracy class of 0.5 according to EN ISO 9513 is used.

Norm: DIN EN ISO 14125, ASTM D 790,, ASTM D 7264, BMW: PR 544, PR500, AA-0630

Plättchen-Biegeversuch ( Rollengelagerter Biegeversuch )

Der Plättchenbiegeversuch nach VDA 238-100 dient zur Ermittlung des Biegewinkels mit dem Ziel, Rückschlüsse auf das Verformungsverhalten und die Anfälligkeit gegenüber Versagen von metallischen Werkstoffen bei Umformprozessen mit dominaten Biegeanteilen oder bei Crashbelastung.

Beim Plättchenbiegeversuch wird eine Biegeprobe in der Prüfeinrichtung ohne Schmierstoffe und auf drehbar gelagerten Auflagerrollen gebogen bis die Kraftabschaltschwelle erreicht ist. Stempelweg und Kraft werden maschinenseitig erfasst. Der Biegewinkel kann entweder aus der Vorschubbewegung des Biegestempels berechnet oder mittels manueller Nachvermessung bestimmt werden.

Normen: VDA-238-100

Plättchen Biegeversuch
Plättchen Biegeversuch
Plättchen- bzw. Rollengelagerter Biegeversuch
Plättchen- bzw. Rollengelagerter Biegeversuch