OEM&Lieferant Ausgabe 2/2021

114 CAE (Computer-Aided Engineering) stands for computer aided development and cov- ers all technical work processes. The fo- cus here is on the thermal and structural mechanical calculation. Both conventional analytical calculation methods, for instance the design of screw connections with VDI 2230, and more complex numeric calcu- lations with the finite element method are used. Thanks to the range of calculation methods available with CAE Services, EJOT is thus able to offer their customers a be- spoke engineering service. The main focus of this innovative support feature is how the respective EJOT connec- tion solution affects the customer compo- nent. Both thermal and mechanical operat- ing loads are able to be taken into account here. The analysis options range from the calculation of multi-part assemblies to the detailed examination of individual bolted joints. The specific advantages of these digital test options are the speed, flexibility and detail. No physical components need to be present, as would be necessary in real-life tests. Even in the early design stages, different variants can be entered into the calculation to identi- fy the most promising design. Thanks to this great insight given into the stress situation of the components, optimizations can be re- liably suggested and implemented. A frequent question from design engineers and developers is about estimating a com- ponent‘s service life. This is typically de- termined in real-life tests by exposing the component to the expected loads. These loads can be characterized by temperature or external forces, for example. Since most technical components have a service life of several years, these tests can only be greatly simplified or carried out with great expenditure of time and money. At this point, users particularly benefit from this digital support, as simulations can be used to esti- mate the service life in a fraction of the real test time. As a result, the technical compo- nent reaches a high degree of maturity early on and real-life component tests can be re- duced to a minimum, significantly shorten- ing development cycles. The self-tapping screws from EJOT are of- ten used in materials which can only be used in calculations once detailed materi- al properties have been identified. These properties extend beyond the specification of the tensile modulus and the flow charac- teristics, especially for thermoplastics and light metals. The basis for CAE Services is a comprehensive material database, which is also based on time-dependent and tem- perature-dependent material effects. This allows the reduction of the clamp load over time due to material fatigue (clamp load re- laxation) to be reliably calculated in order to design an operationally safe screwed con- nection. The customer therefore only has to provide material properties in rare cases for specific projects. This saves time and money on characterization tests for material samples. The figure above shows the section of an assembly created as an example to demon- strate some of the calculation options of the CAE Services. The assembly consists of a housing, gasket, cover and six EVO PT® screws, the latest EJOT development in self-tapping screws for thermoplastic materials. There is a defined operating pressure within the assembly. Our aim is to evaluate the watertightness using CAE Services. Fastening Technology EJOT – The digital development partner for designing screw connections By David Korn, EJOT GmbH & Co. KG, Bad Berleburg For almost 100 years, EJOT has developed and produced high performance connection and fastening solutions. EJOT‘s product portfolio covers a wide range of applications in fastening technology. For many customers, EJOT is already their chosen engineering partner in product and component development. With the help of innovative digital tools, the EJOT application engineers bring custom solutions to life for the challenges their customers face in fastening technology. The fastening technology specialists have expanded their digital service offer with CAE Services, thus shortening the time between queries about the durability of screwed components and testing of components in conventional tests. Graphics: © EJOT GmbH & Co. KG Figure 1: Example application of EJOT CAE Services