FEM best practices and examples - Revision history

Struct4U at 18:54, 5 September 2022

2022-09-05T18:54:14Z

← Older revision		Revision as of 18:54, 5 September 2022
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	===FEM-solver===		===FEM-solver===
	The FEM-solver is written completely in C# with multiple core support. For plates it is geometrically linear. So second order effects are '''not''' taken into account. For beams it is geometrically non-linear. So second order effects are taken into account.		The FEM-solver is written completely in C# with multiple core support. For plates it is geometrically linear. So second order effects are '''not''' taken into account. For beams it is geometrically non-linear. So second order effects are taken into account.

			[[File:FEM concrete.png\|800px]]

	===Mesh element/theory===		===Mesh element/theory===
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	Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal forces will be higher then reality mainly because of point loads, point and linear supports. In reality they have a curtain area. In the model they are points and therefore infinite stress can occur.		Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal forces will be higher then reality mainly because of point loads, point and linear supports. In reality they have a curtain area. In the model they are points and therefore infinite stress can occur.

	First some basics:		'''First some basics'''
	* Element size should '''never''' be '''smaller''' then the '''plate thickness'''. Otherwise the theory of Kirchhoff is not correct anymore.		* Element size should '''never''' be '''smaller''' then the '''plate thickness'''. Otherwise the theory of Kirchhoff is not correct anymore.
	* Element size is at '''least''' '''the''' '''smallest span''' in the structure to expect a correct result.		* Element size is at '''least''' '''the''' '''smallest span''' in the structure to expect a correct result.
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	Workflow to find the right mesh size within a steel structure. Especially around areas with point loads/supports, line loads/supports we need to change our mesh size locally.		Workflow to find the right mesh size within a steel structure. Especially around areas with point loads/supports, line loads/supports we need to change our mesh size locally.

	# Start with a mesh of the ~~thickness~~*2.		# Start with a mesh of the platethickness*2.
	#		#

Struct4U at 10:55, 5 September 2022

2022-09-05T10:55:34Z

← Older revision		Revision as of 10:55, 5 September 2022
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	===Mesher===		===Mesher===
	The mesher is using 4-nodes quadrangle elements because they are more accurate than 3-nodes triangle elements. On a edge there at least 2 elements with an even number.		The mesher is using a 4-nodes quadrangle elements because they are more accurate than 3-nodes triangle elements. On a edge there are at least 2 elements with an even number.
	===Mesh Size===		===Mesh Size===

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	* Element size should '''never''' be '''smaller''' then the '''plate thickness'''. Otherwise the theory of Kirchhoff is not correct anymore.		* Element size should '''never''' be '''smaller''' then the '''plate thickness'''. Otherwise the theory of Kirchhoff is not correct anymore.
	* Element size is at '''least''' '''the''' '''smallest span''' in the structure to expect a correct result.		* Element size is at '''least''' '''the''' '''smallest span''' in the structure to expect a correct result.
	* '''Steel''' '''plate''' structures: If you make ~~you~~ mesh '''50% smaller''' the stress should not increase more then '''10-12%.'''		* '''Steel''' '''plate''' structures: If you make the mesh size '''50% smaller''' the stress should not increase more then '''10-12%.'''

	==== Workflow within a steel structure ====		==== Workflow within a steel structure ====
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	=== Plate on Grade ===		=== Plate on Grade ===

	Within XFEM4U there is an option to support a plate on grade(elastic soil). The elastic soil		Within XFEM4U there is an option to support a plate on grade(elastic soil). The elastic soil

	===[[Plate stresses/forces]]===		===[[Plate stresses/forces]]===

Struct4U at 10:02, 5 September 2022

2022-09-05T10:02:46Z

← Older revision		Revision as of 10:02, 5 September 2022
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	===[[Plate stresses/forces]]===		===[[Plate stresses/forces]]===

	===[[Reinforcement calculation Eurocode]]===		===[[Reinforcement calculation plate Eurocode]]===

	=== Peak moments in concrete plate ===		=== Peak moments in concrete plate ===

Struct4U at 09:59, 5 September 2022

2022-09-05T09:59:54Z

← Older revision		Revision as of 09:59, 5 September 2022
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	Within XFEM4U there is an option to support a plate on grade(elastic soil). The elastic soil		Within XFEM4U there is an option to support a plate on grade(elastic soil). The elastic soil

	=== [[Plate stresses/forces]] ===		===[[Plate stresses/forces]]===

			===[[Reinforcement calculation Eurocode]]===

	=== Peak moments in concrete plate ===		=== Peak moments in concrete plate ===

Struct4U at 13:48, 31 August 2022

2022-08-31T13:48:17Z

← Older revision		Revision as of 13:48, 31 August 2022
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			'''Preface'''

	===FEM-solver===		===FEM-solver===
	The FEM-solver is written completely in C# with. It is geometrically linear. So second order effects are not taken into account.		The FEM-solver is written completely in C# with multiple core support. For plates it is geometrically linear. So second order effects are '''not''' taken into account. For beams it is geometrically non-linear. So second order effects are taken into account.

	===Mesh element/theory===		===Mesh element/theory===
	The mesh element used with in plates in [[XFEM4U]] is a modified [https://en.wikipedia.org/wiki/Bending_of_plates Kirchhoff] element. It is extended in 2021 by [https://nl.wikipedia.org/wiki/Johan_Blaauwendraad Professor Blaauwendraad]. Usually Kirchhoff is less precise regarding shear force distribution. In the modified hybrid element this is solved. Therefore it is a extremely robust mesh element with very reliable shear force distribution.		The mesh element used with in plates in [[XFEM4U]] is a modified [https://en.wikipedia.org/wiki/Bending_of_plates Kirchhoff] element. It is extended in 2021 by [https://nl.wikipedia.org/wiki/Johan_Blaauwendraad Professor Blaauwendraad]. Usually Kirchhoff is less precise regarding the shear force distribution within a plate. In the modified hybrid element this is solved. Therefore it is a extremely robust mesh element with very reliable shear force distribution. For more information check this scientific article about [http://68.183.11.126/struct4u_2021_cement_artikel.pdf this] new element which is completely implemented in XFEM4U.

	===Mesher===		===Mesher===
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	* '''Steel''' '''plate''' structures: If you make you mesh '''50% smaller''' the stress should not increase more then '''10-12%.'''		* '''Steel''' '''plate''' structures: If you make you mesh '''50% smaller''' the stress should not increase more then '''10-12%.'''

	Workflow to find the right mesh size within a steel structure.		==== Workflow within a steel structure ====
			Workflow to find the right mesh size within a steel structure. Especially around areas with point loads/supports, line loads/supports we need to change our mesh size locally.

			# Start with a mesh of the thickness*2.
			#

	=== Plate on Grade ===		=== Plate on Grade ===

			Within XFEM4U there is an option to support a plate on grade(elastic soil). The elastic soil

	Plate ~~Forces~~		=== [[Plate stresses/forces]] ===

	~~[[Plate stresses/forces]]~~		=== Peak moments in concrete plate ===

Struct4U: /* Mesher */

2022-08-28T07:37:29Z

Mesher

← Older revision		Revision as of 07:37, 28 August 2022
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	===Mesh element/theory===		===Mesh element/theory===
	The mesh element used with in plates in [[XFEM4U]] is a modified [https://en.wikipedia.org/wiki/Bending_of_plates Kirchhoff] element. It is extended in 2021 by [https://nl.wikipedia.org/wiki/Johan_Blaauwendraad \| Professor Blaauwendraad]. Usually Kirchhoff is less precise regarding shear force distribution. In the modified element this is solved. Therefore it is a extremely robust element with very reliable shear force distribution.		The mesh element used with in plates in [[XFEM4U]] is a modified [https://en.wikipedia.org/wiki/Bending_of_plates Kirchhoff] element. It is extended in 2021 by [https://nl.wikipedia.org/wiki/Johan_Blaauwendraad Professor Blaauwendraad]. Usually Kirchhoff is less precise regarding shear force distribution. In the modified hybrid element this is solved. Therefore it is a extremely robust mesh element with very reliable shear force distribution.

	===Mesher===		===Mesher===
	The mesher is using 4-nodes quadrangle elements because they are more accurate than 3-nodes triangle elements. On a edge		The mesher is using 4-nodes quadrangle elements because they are more accurate than 3-nodes triangle elements. On a edge there at least 2 elements with an even number.
			===Mesh Size===

			Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal forces will be higher then reality mainly because of point loads, point and linear supports. In reality they have a curtain area. In the model they are points and therefore infinite stress can occur.

			First some basics:
			* Element size should '''never''' be '''smaller''' then the '''plate thickness'''. Otherwise the theory of Kirchhoff is not correct anymore.
			* Element size is at '''least''' '''the''' '''smallest span''' in the structure to expect a correct result.
			* '''Steel''' '''plate''' structures: If you make you mesh '''50% smaller''' the stress should not increase more then '''10-12%.'''

			Workflow to find the right mesh size within a steel structure.

			=== Plate on Grade ===

	~~===Mesh Size===~~

	~~Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal forces will be higher then reality. First some basics.~~		Plate Forces
	* Element size should never be smaller then the plate thickness. Otherwise the theory of Kirchhoff is not correct anymore.
	* Element size also at least the smallest spansize in the structure to expect a correct result.
	* Steel plate structures: If you make you mesh 50% smaller the stress should not increase more then 10-12%.

	~~Workflow to find the right meshsize within a steel structure.~~		[[Plate stresses/forces]]

Struct4U at 07:21, 28 August 2022

2022-08-28T07:21:55Z

← Older revision		Revision as of 07:21, 28 August 2022
Line 1:		Line 1:

			===FEM-solver===
			The FEM-solver is written completely in C# with. It is geometrically linear. So second order effects are not taken into account.

			===Mesh element/theory===
			The mesh element used with in plates in [[XFEM4U]] is a modified [https://en.wikipedia.org/wiki/Bending_of_plates Kirchhoff] element. It is extended in 2021 by [https://nl.wikipedia.org/wiki/Johan_Blaauwendraad \| Professor Blaauwendraad]. Usually Kirchhoff is less precise regarding shear force distribution. In the modified element this is solved. Therefore it is a extremely robust element with very reliable shear force distribution.

			===Mesher===
			The mesher is using 4-nodes quadrangle elements because they are more accurate than 3-nodes triangle elements. On a edge



	===Mesh Size===		===Mesh Size===
	The mesh element used with in XFEM4U is a modified [https://en.wikipedia.org/wiki/Bending_of_plates Kirchhoff] element. It is extended in 2021 by [https://nl.wikipedia.org/wiki/Johan_Blaauwendraad \| Professor Blaauwendraad]. Usually Kirchhoff is less precise regarding shearforce distribution. In the modified element this is solved.

	Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal forces will be higher then reality. First some basics.		Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal forces will be higher then reality. First some basics.
	* Element size should never be smaller then the plate thickness. Otherwise the theory of Kirchhoff is not correct anymore.		* Element size should never be smaller then the plate thickness. Otherwise the theory of Kirchhoff is not correct anymore.
	* Element size also at least the smallest spansize in the structure to expect a correct result.		* Element size also at least the smallest spansize in the structure to expect a correct result.
	* Steel plate structures: If you make you mesh 50% smaller the stress should not ~~increate~~ more then 10-12%.		* Steel plate structures: If you make you mesh 50% smaller the stress should not increase more then 10-12%.

	Workflow to find the right meshsize within a steel structure.		Workflow to find the right meshsize within a steel structure.

Struct4U at 06:33, 25 August 2022

2022-08-25T06:33:02Z

← Older revision		Revision as of 06:33, 25 August 2022
Line 1:		Line 1:

	===Mesh Size===		===Mesh Size===
	The mesh element used with in XFEM4U is a modified [https://en.wikipedia.org/wiki/Bending_of_plates \| Kirchhoff] element. It is extended in 2021 by [https://nl.wikipedia.org/wiki/Johan_Blaauwendraad \| Professor Blaauwendraad]. Usually Kirchhoff is less precise regarding shearforce distribution. In the modified element this is solved.		The mesh element used with in XFEM4U is a modified [https://en.wikipedia.org/wiki/Bending_of_plates Kirchhoff] element. It is extended in 2021 by [https://nl.wikipedia.org/wiki/Johan_Blaauwendraad \| Professor Blaauwendraad]. Usually Kirchhoff is less precise regarding shearforce distribution. In the modified element this is solved.

	Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal forces will be higher then reality. First some basics.		Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal forces will be higher then reality. First some basics.

Struct4U at 05:01, 25 August 2022

2022-08-25T05:01:06Z

← Older revision		Revision as of 05:01, 25 August 2022
Line 1:		Line 1:

	===Mesh Size===		===Mesh Size===
	The mesh element used with in XFEM4U is a modified [[https://en.wikipedia.org/wiki/Bending_of_plates \| Kirchhoff]] element. It is extended in 2021 by https://nl.wikipedia.org/wiki/Johan_Blaauwendraad \| Professor Blaauwendraad]]. Usually Kirchhoff is less precise regarding shearforce distribution. In the modified element this is solved.		The mesh element used with in XFEM4U is a modified [https://en.wikipedia.org/wiki/Bending_of_plates \| Kirchhoff] element. It is extended in 2021 by [https://nl.wikipedia.org/wiki/Johan_Blaauwendraad \| Professor Blaauwendraad]. Usually Kirchhoff is less precise regarding shearforce distribution. In the modified element this is solved.

	Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal forces will be higher then reality. First some basics.		Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal forces will be higher then reality. First some basics.

Struct4U: Created page with " ===Mesh Size=== The mesh element used with in XFEM4U is a modified Kirchhoff element. It is extended in 2021 by https://nl.wikipedia.org/wiki/Johan_Blaauwendraad | Professor Blaauwendraad]]. Usually Kirchhoff is less precise regarding shearforce distribution. In the modified element this is solved. Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal..."

2022-08-25T05:00:41Z

Created page with " ===Mesh Size=== The mesh element used with in XFEM4U is a modified Kirchhoff element. It is extended in 2021 by https://nl.wikipedia.org/wiki/Johan_Blaauwendraad | Professor Blaauwendraad]]. Usually Kirchhoff is less precise regarding shearforce distribution. In the modified element this is solved. Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal..."

New page

===Mesh Size===
The mesh element used with in XFEM4U is a modified [[https://en.wikipedia.org/wiki/Bending_of_plates | Kirchhoff]] element. It is extended in 2021 by https://nl.wikipedia.org/wiki/Johan_Blaauwendraad | Professor Blaauwendraad]]. Usually Kirchhoff is less precise regarding shearforce distribution. In the modified element this is solved.

Below we describe a method how to find the right mesh size for your structure. If you make the mesh too dense, internal forces will be higher then reality. First some basics.
* Element size should never be smaller then the plate thickness. Otherwise the theory of Kirchhoff is not correct anymore.
* Element size also at least the smallest spansize in the structure to expect a correct result.
* Steel plate structures: If you make you mesh 50% smaller the stress should not increate more then 10-12%.

Workflow to find the right meshsize within a steel structure.