fresh green beans and other high turgor vegetable, and potato chips and other snack items. Snap, meaning to break suddenly upon the application of a force, is a desirable textural property in most crisp foods, e.g. Foods that exhibit fracturability are products that possess a high degree of hardness and low degree of adhesiveness. Fracture and/or yielding then become the salient features. In the case of food normally testing involves large deformations. These breaking/bending characteristics can be very important measurement for materials where a high degree of strength may be required with a degree of flexibility so that a material does not shatter easily on small application of stress. The amount of deformation the sample will absorb before it fails may also be of interest. Usually the product is stressed until it breaks and the force required to do so is measured. It is a versatile test (mostly commonly a 3 point bend test) and can be applied to many types of products that are available in, or can be cut or shaped into, elongated test beams. Snapping and bending tests are usually applied to products that are in the shape of a bar or sheet. In this case it is recommended that a maximum data acquisition rate is selected, i.e., 2000 points per second, to collect as much detail in the short duration of time as possible. When performing tests on samples that fracture or break quickly the duration of this type of test is very short (often less than 1 second). Examples are cutting of material, compression and biting between wedges. Fracture properties also can be studied by less well defined methods of deformation that may nevertheless yield real material characteristics. Fracture mostly starts on the outside of the tensed part of the sample and therefore can be observed.īasic cylinder probes may also be used for fracturability testing, for example, for assessing tablet fracturability in a Diametral Crushing Test. Bending tests are often used in materials testing, possible because they are easy to perform and it is not necessary to fix the specimen to an apparatus. Stable Micro Systems enables a wide range of tests in this field, using fixtures such as the Three Point Bend Rig which are adaptable to many types of sample, and also specialist attachments like the Crisp Fracture Support Rig or the Spaghetti Flexure Rig.īending is a combination of compression, tension and some shear. If a break does not occur whilst the sample is flexed then a measure of its flexibility can be performed instead – a degree of flexibility can be desirable or a characteristic to be avoided, depending upon the sample. This type of test can measure the fracture and break strength of hard and brittle products (or their flexibility) by bending the sample, usually until a break occurs. World leaders in texture analysis and volume measurement FIND OUT WHY
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