Finite element analysis is a kind of solving questions about a series of partial differential equations of the numerical method, finite element analysis in mechanical engineering has been widely applied to the structure, vibration and heat transfer on issues such as, used to solve various problems from simple to complex, it is analysis in the process of product development and improve the design of a strong engineering analysis tools。
In the process of research and development and the improvement of injection molding machine, the finite element analysis has greatly improved the design quality and design cycle, especially in the stress of the template and pull rod structure analysis, finite element analysis has become an essential tool. With donghua machinery co., LTD. The two machine 4 000 (clamping force of 4000 tons), for example, in the process of structural design, template and pull rod of general finite element analysis process is composed of the following four steps: 1 to establish mathematical model established mathematical model including the mechanical model and three-dimensional entity model, a mechanical model is loading mode of mechanical parts, size and accurate judgement in the form of fixed while the three-dimensional solid model without destroying as far as possible on the basis of simplified mechanical model, to differentiate the grid of high quality, such as shown in 4000 simplified mathematical model of rod and the nut.
2 to establish finite element model is established in this paper the finite element model is carried out on the model discretization processing, also known as the meshing, the geometric entity split into relatively small and simple shape (called finite element), the shape of the entity (unit) in principle is arbitrary. Two-dimensional problem generally adopts the triangular or rectangular units, three dimensional space can use tetrahedron or polyhedron, injection molding machine parts analysis commonly used tetrahedron grid, as shown in the finite element model of fixed template for 4, 000.
Dynamic template displacement calculation of finite element model for calculating the finite element model is the continuum with finite element discretization, based on the finite unit as a piece-wise interpolation for solving all kinds of mechanics, the numerical method of a physical problem. The finite element method is a finite element of the continuum: the unit of the structure of the bar is each one. The unit of a continuum is the unit of various shapes (such as triangles, quadrangle, hexahedron, etc.). A function of each unit is simple field nodes with only a finite number of undetermined parameter function, the collection of these units field function to approximate the whole continuum field function. According to the energy equation or weighted residual equation can be established finite algebraic equations of the undetermined parameter, solving the numerical solution of discrete equations by finite element method (fem), and then using the direct method or comprehensive iteration method for the solution of the model, this software will be done automatically.
4 analysis results of finite element analysis for researchers to provide mechanical systems, such as stress, deformation diagram, the diagram will is the important basis of correction and improve the design. Finite element analysis of the key step is the analysis of the result data, only the result of the convergence data is available for the results of the data, the software usually convergence preliminarily determine whether the results, and analyze the data you need to find the most close to the convergence value of data as a basis to determine the design and improvement, which requires researchers to establish many times different grid size of discrete model were analyzed, and the server's configuration is limited, however, the researchers could not to an infinite number of discrete model, so find a local model or model (key) to what extent are discrete get close to the convergence value is the key to accurate analysis results (error should be within the permitted error in engineering), as shown in the stress analysis results in figure 4 000 dynamic template, such as 4000 displacement analysis of the dynamic template shown in figure (i.e., deformation analysis diagram).
The action template should be tried in.
5 key or conclusion with the finite element analysis tool to participate in the production practice, analysis is not under any circumstances one hundred percent reliable, analysis can not replace the practice, in order to make the analysis of the practice of little detours, to ensure the reliability of the design.