Al-Araji Zainab Hussam Mosa – Undergraduate,
Department Radio Equipment Engineering and Manufacturing, Voronezh State Technical University E-mail: alaraje@bk.ru
A.V. Muratov – Dr.Sc.(Eng.), Professor,
Department Radio Equipment Engineering and Manufacturing, Voronezh State Technical University E-mail: kipr@vorstu.ru
A.V. Turetsky – Ph.D.(Eng.), Associate Professor,
Department Radio Equipment Engineering and Manufacturing, Voronezh State Technical University E-mail: tav7@mail.ru
Electronic modules of modern devices are an assembly of a large number of printed circuit boards housed in a rugged mechanical case. On the printed circuit board is a number of components, including those with significant mass and area. During operation, the unit is exposed to various types of loads, such as vibrations and shocks. To speed up the design time and, thereby, increase the efficiency, computer simulation is widely used. One of the key tasks of engineering machine analysis is its accuracy. The article provides information on modeling a large enough area of a printed circuit board by means of Creo and a comparison is made with the results of the test on a vibration stand.
Printed circuit boards are the main supporting structure of electronic devices that perform a dual function: mechanical fastening of components and their electrical connection. During operation, boards are affected by shocks, vibrations and static loads. At increased loads on the board, there is a violation of the integrity of the solder joints, their detachments and detachments from the base fiberglass. This is especially true of the largest components in terms of area, for example, with BGA type enclosures. When designing a printed circuit board, it is necessary to consider the installation sites of such components, taking into account the mechanical characteristics of the board.
The finite element method (FEM) is widely used to analyze the mechanical properties of the board. As a result, the vibrational response of the board is calculated, and the natural frequencies are determined, as well as the most loaded areas in which it is undesirable to locate components with a large area. In addition, you can define some failure criteria of certain components to show whether the installed components can withstand the resulting curvature or acceleration.
Finite element models can be simplified or, conversely, detailed. Detailed models of finite elements are constructed by modeling both the printed circuit board and the components. However, this approach is rarely used because it is time consuming and quite expensive. Instead, models of printed circuit boards are simplified, where the geometry of the components is neglected. For analyzing the mechanical properties of the board in Creo there is such a tool as «concentrated mass». Instead of the actual geometry of the component, you can put a point equivalent with a mass equal to the mass of the component. Of course, this is a certain simplification, but it seriously speeds up the modeling process.
As a result, the following was clarified.
When designing a printed circuit board and analyzing its mechanical properties, the FEM method is usually used. Studies by other scientists have shown its applicability to boards and a good correlation with the results of experiments. To further accelerate the vibration analysis of the board, it is proposed to use such a tool as «concentrated mass» during FEM, replacing the real geometry of the components located on the board. The results of the experiment of vibration properties of the armor given in the article showed good correlation with the results of modeling using Creo Elements / Pro 5.0.
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