Corrugated cardboard is often used as container in warehousing and storage. In the field the containers potentially have to carry their loads for a period of many month - thereby undergoing a multiplicity of changes in relative humidity and temperature. In order to effectively and reliably determine the long term load-carrying ability of the materials under those stress factors, creep test are an essential testing procedure.
The Hegewald & Peschke MPT GmbH has developed two new devices for creep tests on corrugated board under the influence of climate and the loading through weights. With those creep test devices compression tests and bending tests on boards can be carried out. They are designed for the use in a climate chamber, but can also be applied as table devices at room temperature.
The specimens can be tested either edgewise in compression tests or flat-wise in bending tests, depending on the device. The performance of corrugated board in these procedures is the crucial factor in determining the container strength in dynamic tests.For compression tests the specimens are placed in the creep testing device and loaded with appropriate weights. Under the influence of load as well as the cyclic changes of humidity and temperature the specimens swell and shrink. Besides the specimen height decreases during a longer loading period progressively. The second creep testing device is designed for 4-point-bending tests. Due to the fact, that creep tests necessarily require a longer period of time, both devices are equipped with 4 specimen spaces for an efficient test procedure.