1.If the same problem is solved using finite element method and finite difference method, how much variation in results is expected?
2. How do you decide which method to use for a particular problem?
3. For problem related to geotechnical engineering which is good (FEM software like Plaxis and Abaqus or FDM software like Flac)?
4. For modeling rock which software is good?
Hi Sunil,
Before answering your questions, let me give you the background of both the methods.
FEM solves the physical problem by dividing the geometry into small elements and calculates the stresses and strains in those elements before assembling them back using theory of superposition.
However, FDM divides the problem into small time steps and predicts the stresses and strains of the next time step based on the present time step using finite difference formulation such as forward, backward and central differences.
Now, let me answer your questions,
1. Little difference is expected
2. If you are solving problem involving static loads, suggest you to go for FEM. If you are solving dynamic problems (which depends on time), go for FDm for better accuracy.
3. Plaxis is simple and good for solving simple geotechnical problems.
Abaqus is good...but is not exclusive for geotechncial problems. It is a general purpose civil engineering software. You will not find variety of materials models suiting the geomaterials.
I suggest, FLAC is better compared to other two softwares. You can solve almost all geotechnical problems in FLAC. Only drawback is,it is command driven and hence, initially it consumes some time to get the feel of the software. But once you understand, it can solve any problem. It gives wide range of material models.
4. FLAC
Hope my answers are useful. Thanks.
Hello,
My opinion;
If the FDM program the algorithm is less expensive from the computational point of view, compared to FEM. The two will solve the differential equation but is more refined results with FEM.
If the rock mass is continuous, Plaxis is a good software.
If the rock mass is not continuous, is due to analyze discrete fracture network DFN.
Before performing the numerical model is important to identify the failure mechanism, which controls the stability, later decide which method.
Warm Regards
1: not much difference is expected.
2: it's upto you to decide. Software will not solve you problem. It's just a tool to help you.
3: you can use software provided it has the capability to do for what you are planning.
4: you can use software that has the capability to analyze problem in which concept of rock mechanics can be applied
Hi Sunil,
Before answering your questions, let me give you the background of both the methods.
FEM solves the physical problem by dividing the geometry into small elements and calculates the stresses and strains in those elements before assembling them back using theory of superposition.
However, FDM divides the problem into small time steps and predicts the stresses and strains of the next time step based on the present time step using finite difference formulation such as forward, backward and central differences.
Now, let me answer your questions,
1. Little difference is expected
2. If you are solving problem involving static loads, suggest you to go for FEM. If you are solving dynamic problems (which depends on time), go for FDm for better accuracy.
3. Plaxis is simple and good for solving simple geotechnical problems.
Abaqus is good...but is not exclusive for geotechncial problems. It is a general purpose civil engineering software. You will not find variety of materials models suiting the geomaterials.
I suggest, FLAC is better compared to other two softwares. You can solve almost all geotechnical problems in FLAC. Only drawback is,it is command driven and hence, initially it consumes some time to get the feel of the software. But once you understand, it can solve any problem. It gives wide range of material models.
4. FLAC
Hope my answers are useful. Thanks.
Please check the blog below to get a detailed answer. Thanks
https://caendkoelsch.wordpress.com/2017/11/04/the-difference-between-fem-fdm-and-fvm/
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