Introduction:

In the process of designing Network equipment for outdoor installations, it is essential to evaluate the seismic stability of brackets to prepare for potential earthquakes. Particularly crucial is determining whether the bolts applied to the brackets would withstand seismic forces.

How to apply boundary condition and load :

In the process of creating the analysis model, connection points were modeled using RBE3 and Bolt elements to generate a Finite Element (FE) model. Additionally, to streamline the overall analysis time, internal parts of the communication equipment were represented as mass elements considering their weight, with the main focus of the analysis being on the brackets and bolts.

Response spectrum analysis :

The response spectrum applied in this analysis adhered to the Earthquake Test Methods outlined in Network Equipment - Environmental Test Method 5.4.1. Load conditions were applied in each direction, and prior to analysis, modal analysis was conducted to analyze the dynamic characteristics of each direction. To enhance the reliability of the analysis, modal analysis was carried out until valid mode shapes with a mass participation ratio of over 80% were obtained, resulting in mode shapes ranging from a minimum of 28Hz to a maximum of 775Hz.

Analysis results :

Response spectrum analysis was conducted, and the maximum stresses in each direction were analyzed. The analysis compared the maximum stress values with the yield strength of the material to assess safety. Furthermore, considering the tensile and shear strengths of the bolts, the results were analyzed to ultimately verify safety.

Tips : 

This analysis was performed using midas NFX, which provides a database for various seismic loads. With its intuitive user interface, midas NFX enables not only expert analysts but also designers to conduct analyses directly.

Overall, this article sheds light on the crucial process of validating the seismic resistance of Network equipment mount brackets, underscoring the importance of meticulous design considerations in ensuring safety and reliability in the face of seismic events.