Finite element method for the construction of the approximation of the solution

In summary, the conversation discusses a two-point problem involving a differential equation with given conditions and a finite element method for approximating the solution. The method involves taking a function from the finite element space and using it to solve the equation. The function must satisfy certain conditions in order for the method to be correct.
  • #1
mathmari
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Hey! :eek:

Given the following two-point problem:
$$-y''(x)+(by)'(x)=f(x), \forall x \in [0,1]$$
$$y(0)=0, y'(1)=my(1)$$
where $ b \in C^1([0,1];R), f \in C([0,1];R)$ and $ m \in R$ a constant.
Give a finite element method for the construction of the approximation of the solution $y$ of the problem above, where the finite element space ($S$) consists of continuous and partially linear functions.

My idea is the following:
$ u \in S:$
$$ -\int_0^1{u''g}dx+ \int_0^1{bu'g}dx= \int_0^1{fg}dx$$
$$ -u'g|_0^1+ \int_0^1{u'g'}dx+ \int_0^1{bu'g}dx= \int_0^1{fg}dx$$
$$-mu(1)+g(1)+ \int_0^1{u'g'}dx+ \int_0^1{bu'g}dx= \int_0^1{fg}dx$$
$ \forall g \in S$

Could you tell me if this is correct?
 
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  • #2
To find the method we take a function $g$ of $S$, right? Does this function satisfy the conditions of the problem? I mean $g(0)=0, g'(1)=mg(1)$... Or is there an other way to find the method?
 

FAQ: Finite element method for the construction of the approximation of the solution

What is the finite element method?

The finite element method (FEM) is a numerical technique used to approximate the solution of a partial differential equation by dividing the problem into smaller subdomains, called finite elements. It is commonly used in engineering and scientific applications to solve complex problems that cannot be easily solved analytically.

How does the finite element method work?

The finite element method works by dividing a complex problem into smaller, simpler subdomains, called finite elements, and then constructing an approximation of the solution within each element. These elements are connected at shared points, called nodes, and the overall solution is obtained by combining the solutions from each element.

What are the advantages of using the finite element method?

One of the main advantages of the finite element method is its ability to handle complex geometries and boundary conditions. It can also provide accurate solutions for problems with irregular or discontinuous material properties. Additionally, the method allows for efficient use of computational resources, making it suitable for solving large-scale problems.

What are the limitations of the finite element method?

While the finite element method is a powerful tool, it does have some limitations. It is not suitable for problems with sharp corners or singularities, and the accuracy of the solution is highly dependent on the quality of the mesh used. Additionally, the method can become computationally expensive for problems with very large numbers of elements.

How is the solution from the finite element method validated?

The accuracy of the solution obtained from the finite element method can be validated by comparing it to analytical solutions, if available, or by using convergence studies where the solution is refined with smaller and smaller element sizes. It is also common to validate the results by comparing them to experimental data or results from other numerical methods.

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