Bending and Torsion Testing

Bending Test

During bending tests, deformation occurs at the midpoint of the test material, and the bending force causes a concave surface or a bending from fracture. Bending tests are typically performed to determine the ductility or resistance of said material to fracture. During these tests the material is shaped into a certain shape. Force is applied to the test sample at its midpoint to form a concave surface with a radius of curvature determined according to the underlying standard. Bending tests in various sectors are as common as tensile testing, compression testing and fatigue testing.

The bending test of a material allows the determination of the flexibility, flexural strength, fracture strength and fracture resistance of the material. These properties show the behavior of a material under pressure. Materials failing under pressure may cause undesirable consequences in the future. For example, in any construction process, the use of ductile materials loaded with bending forces is always a risk. If a material starts to break or completely break during a twist test at three or four points, it is inevitable that this material will cause a disaster in any construction.

In practice, there are various bending tests performed by advanced laboratories. One of these is the guided twist test. The sample to be tested is placed horizontally along the two supports and then a force is applied to the midpoint that deforms the sample in a U-shape. A bending test is a semi-guided twist test. During this test, the midpoint of the sample is bent at an angle or internal radius. The third method of bending is the free twist test. Here the ends of the sample are pushed together, but no force is applied to the twist itself. Finally another twist test is a common fracture toughness test. This test method is described in the ASTM E399 standard designed by the American Testing and Materials Organization (ASTM) (ASTM E399 - 17 Standard test method for linear-elastic plane-tensile fracture toughness of metallic materials). During this commonly applied test, a three-point bending armature is used to apply the midpoint force to the opposite face without breaking, and the highest value reached by the crack defined below the midpoint is determined.

In general, bending tests are performed on metals or metallic materials. However, other materials that may be subjected to plastic deformation, such as polymers and plastic materials, may also be applied to this test. Such materials may be of any shape possible, but the materials to undergo a bending test are mostly sheets, strips, rods, coatings and tubes. Bending test machines are generally used in materials with an acceptable ductility.

Bending tests are also used for welding. The purpose of these tests is to ensure that the weld is properly welded to the base metal and to demonstrate how resistant the weld itself is to bending stresses. In this way, it is assured that the weld does not carry a defect that could cause it to fail under any pressure. During the test, the weld sample is deformed by guiding the bending test to form a “U an that exposes both the material on the outer surface to the tensile force and the pressure force of the material on the outer surface. If the weld holds and shows no signs of cracking, the weld is of acceptable quality.

EUROLAB also offers bending testing services in a wide range of laboratory services. Thanks to these tests, enterprises receive more efficient, high performance and quality testing services and provide safe, fast and uninterrupted service to their customers.

In addition to the bending test services provided within the scope of laboratory services, EUROLAB also provides other testing services.