## Element Size Recommendations

Element Size Recommendations At Welds For DVS 1612

The DVS 1612 makes use of the nominal stress concept when assessing welds for fatigue. The increase in stress caused by the shape of the construction and the weld seam itself is taken into account by notch case dependent fatigue strength values, which can be found in the tables from the appendix B (DVS 1612:2014-08).

In FEA's the nominal stresses should be gathered at a specific evaluation distance in order to make sure, stress increases resulting from the shape of construction are not taken into account. The DVS 1612 recommends an evaluation distance of 1 to 1,5 times the sheet thickness from the weld seam transition.

WeldFEM calculates the evaluation distance for the assessment standard DVS 1612 by 1,5 times the sheet thickness from the weld seam transition.

To make sure that WeldFEM gathers mainly nominal stresses out of the plate-elements, we recommend to set up at least one row of elements at the weld junction, where the element edge lengths are equal to the size its sheet.

By doing that it is ensured that at least two rows of elements are taken into account for the weld assessment.

The following picture shows the element edge lengths at the weld junction and the evaluation distances, which are illustrated by the red curves.

Element Size Recommendations At Welds For DVS 1608

The DVS 1608 makes use of the nominal stress concept when assessing welds for fatigue. The increase in stress caused by the shape of the construction and the weld seam itself is taken into account by notch case dependent fatigue strength values, which can be found in the tables from the appendix B (DVS 1612:2014-08).

In FEA's the nominal stresses should be gathered at a specific evaluation distance in order to make sure, stress increases resulting from the shape of construction are not taken into account. The DVS 1608 recommends an evaluation distance of 5 mm plus half the length of the strain gauge from the weld seam transition. In this case, half the length of the strain gauge is equal to 5 mm.

WeldFEM calculates the evaluation distance for the assessment standard DVS 1608 as follows: 10 mm from the weld seam transition. To make sure that WeldFEM gathers mainly nominal stresses out of the plate-elements, we recommend to set up at least one row of elements at the weld junction, where the element edge lengths are equal to the size of its sheet.

By doing that it is ensured that at least two rows of elements are taken into account for the weld assessment.

The following picture shows the element edge lengths at the weld junction and the evaluation distances, which are illustrated by the red curves.

Element Size Recommendations At Welds For DIN EN 13001-3-1

The DIN EN 13001-3-1 makes use of the nominal stress concept when assessing welds for fatigue. The increase in stress caused by the shape of the construction and the weld seam itself is taken into account by notch case dependent fatigue strength values, which can be found in the table D.3 from the appendix D (DIN EN 13001-3-1:2012-09).

In FEA's the nominal stresses should be gathered at a specific evaluation distance in order to make sure, stress increases resulting from the shape of construction are not taken into account. The DIN EN 13001-3-1 gives no recommendations regarding an evaluation distance. Since the DVS 1612 is also based on the nominal stress concept, the recommendation for estimating the evaluation distance can be adopted.

WeldFEM calculates the evaluation distance for the assessment standard DIN EN 13001-3-1 as follows: 1,5 times the sheet thickness from the weld seam transition. To make sure that WeldFEM gathers mainly nominal stresses out of the plate-elements, we recommend to set up at least one row of elements at the weld junction, where the element edge lengths are equal to the size of its sheet.

By doing that it is ensured that at least two rows of elements are taken into account for the weld assessment.

The following picture shows the element edge lengths at the weld junction and the evaluation distances, which are illustrated by the red curves.