Lecture 3: Solid Element and Adaptive Meshing Techniques

What are the two types of edges for solid elements?

Straight edges and curvilinear edges.

What distinguishes curvilinear edges from straight edges?

Curvilinear has more nodes, and has access to more types of loads.

Between straight edges and curvilinear edges, which one (or element order) is the default option used by SolidWorks?

Curvilinear, also known as second Tet elements.

Does the size (not order) of the Tet element affect the accuracy of the values computed?

No, it is purely cosmetic.

Tet element is short for?

Tetrahedral element

What is the purpose of a convergence test in solid element meshing?

To ensure that consecutive mesh refinement leads to consistent, accurate results in stress and displacement results.

What is the recommended turn angle for concave elements?

30 degrees or less.

When conducting a convergence test, how many tetrahedral elements must we start with?

At least 2 to 3 tetrahedral elements.

What does the aspect ratio measure in solid elements?

The ratio between the longest edge and the shortest normal dropped from a vertex to the opposite face normalized with respect to a perfect tetrahedral.

What does the Jacobian ratio measure in solid elements?

It measures the curvature of edges and distortion at the mid-side node when using second-order tet elements.

What are the three types of mesh density mentioned?

Coarse mesh, default mesh, and fine mesh.

Standard mesh has options to modify the magnitude of the global element size and the magnitude of its tolerance. What percent of the global size is used as its tolerance?

5% of the global size.

What percent of the smallest mesh element size is defined in the mesh control property manager?

30% of the smallest mesh element size.

True or false. For our assignments, automatic transition must be enabled when meshing a part.

False, must be disabled in our cases.

Which type of mesh is used as the standard mesh type in the industry?

Curvature-based mesh.

What is mesh control?

The ability to set certain mesh sizes at specific areas; corners, fillets, etc.

How does mesh refinement affect stress and displacement results?

Mesh refinement can significantly affect the accuracy of stress and displacement results up to a certain point.

What is the purpose of the minimum feature size check in mesh refinement?

It ensures that the mesh can accurately capture the smallest features of the model.

What are the two types of mesh refinement techniques?

Global mesh refinement and local mesh refinement.

What is the purpose of the mesh control feature in solid elements?

Mesh control determines the size of the element locally on selected entities independent of the global element size.

Why would we apply mesh control to fillets?

Mesh control can be applied to fillets to ensure appropriate mesh density and in turn more accurate values for the part.

What is the significance of the Trend Tracker Tool during mesh refinement? Why would we use it?

It helps track changes in the results with regards to mesh quality. It is crucial for convergence tests.

What is "Energy Norm Error" in the context of mesh refinement? What does it relate to? What does it NOT relate to?

It is a measure of discontinuity between tet elements during the simulation. It directly relates to discretization error. It does not relate to the accuracy of the calculated stress.

What is the purpose of automatic transitions when generating a standard mesh? In what cases should we disable it?

It automatically applies mesh control to small features. Disable it if your part has many small features.

What is the relationship between solid element size and mesh density?

Smaller solid element sizes generally lead to higher mesh density, which can improve simulation accuracy.

What is the role of adaptive meshing in solid elements?

Adaptive meshing adjusts the mesh density based on the solution requirements to improve accuracy.

What does 'manual mesh refinement tools' refer to?

Tools that allow users to manually adjust the mesh density and quality in specific areas of the model.

What is curvature-based mesh? What is it for?

SolidWorks creates more elements in higher-curvature areas automatically, eliminating the need for mesh control.

What does the Ratio parameter in mesh control specify?

It specifies the ratio between sizes in consecutive transitional element layers.

What causes stress singularity in finite element analysis? What theory is it based on?

Stress singularity occurs due to sharp corners, where stress is theoretically infinite according to the theory of elasticity.

What are the three types of meshing methods in FEA?

Standard, H-adaptive, and P-adaptive methods.

How does the H-adaptive method refine mesh density?

It applies mesh control automatically in several iterations, adapting to the stress pattern.

What does SolidWorks do to obtain the target accuracy when H-adaptive meshing is used?

It changes the size of the elements.

What is a limitation of H-elements in the H-adaptive method?

H-elements retain their order and cannot be upgraded to a higher order.

What is the maximum number of iterations for the H-adaptive method?

The maximum is five iterations, which may increase with higher target accuracy.

What distinguishes the P-adaptive method from the H-adaptive method?

The P-adaptive method changes the element order without refining the mesh, while H-adaptive focuses on mesh refinement.

What is the maximum number of loops in the P-adaptive method?

The maximum is four loops.

Why bother using P-adaptive meshing?

It is useful for large or complicated parts.

What is the recommended local element size for high accuracy?

Local element size can be set to 0.1 mm.

What is the definition of “global element size” in the context of meshing?

The global element size is the overall size of elements used in the mesh, which can be set to 1 mm.

What is the significance of the element size growth ratio?

It specifies how element sizes grow from regions of high curvature in all directions.

What is the outcome of using the standard meshing method?

It requires manual refinement of mesh density and a convergence test.

How does the H-adaptive method relate to strain energy error?

It is adapted to the stress pattern based on strain energy error, not stress error.

What is the effect of sharp corners in a model during finite element analysis?

They can lead to stress singularity, complicating the analysis.

The smallest wall thickness of a part is 4 mm. What would be the acceptable minimum size of the element to start mesh refinement using SolidWorks simulation? A) 8 mm B) 4 mm C) 3 mm D) 1 mm

1 mm. Start with at least 2-3 elements. With a wall thickness of 4 mm, 1 mm guarantees at least said amount.

The convergence test is used in Finite Element Analysis to address: A) Idealization Error B) Numerical Error C) Discretization Error D) Interpretation Error

Discretization error