Numerical analysis and validation of a complex
structure under loading
Appendix 1: Pipe fitting analysis
This assignment represents a typical mechanical engineering problem. A pipe holder has
been designed to ensure that a pipe connection under internal pressure (5 MPa) is held
adequately in place without excessive stresses in either the pipe or the pipe holder.
The problem consists of 5 parts (1 pipe section, 2 pipe holder sections and 2 bolts). All
dimensions are in mm. You are to assume that bolt stresses are not critical, hence the bolt
does not need to be modelled in detail and can be replaced by simplified fastener solutions
as discussed in this course.
Figure 1: (a) different parts for the problem and (b) assembled model with applied loads. Here we
assume that the pipe holder is fixed at the lower flange.
Assignment-specific tasks:
In line with the mandatory report elements, please complete the following required analysis
elements. It is expected that you elaborate on all necessary and modelling details,
assumed simplifications and interesting findings in your report:
- Mesh refinement study
- Mesh type investigation study
- Constraint selection discussion for assembly (Coupling, TIE and Contact)
- Vibration analysis to show that the parts of the mesh are properly connected
- Linear perturbation step for detailed stress analysis under internal pressure
- Suggest and validate a model change of the pipe fitting to reduce cost / weight.
Appendix 2:
Appendix 2: Hip joint analysis
This assignment represents a typical biomechanical engineering problem. Hip osteotomy
is a commonly performed surgical procedure. Here, a simplified CAD model of the hip joint
is provided as follows. The joint is composed of three parts, i.e., the femoral head,
intermediate cartilage layer and acetabulum. Initially we wish to investigate the stresses
for all parts in direct alignment. Therefore, the outer surface of the acetabulum should be
fixed in all directions and a load of 1500 N in axial direction should be applied to the bottom
surface of femoral head instance, representing the acting force during normal standing in
the hip joint. Note that boundary conditions should be appropriately interpreted for the finite
element analysis based on your underpinning knowledge. The mechanical properties of
the different biological materials are provided in Table 2. All model dimensions are in mm.
Assignment-specific tasks:
In line with the mandatory report elements, please complete the following required analysis
elements. It is expected that you elaborate on all necessary and modelling details,
assumed simplifications and interesting findings in your report.
- A mesh refinement study
- A mesh type investigation study
- Constraint selection discussion for assembly (Coupling, TIE and Contact)
- Vibration analysis to show that the three parts are properly connected in the
assembly. - Linear perturbation step for detailed stress analysis.
- Assume that a 30° angle change around the centre point of the femoral head with
respect to the cartilage and acetabulum may occur, which represents different
stages of the human gait cycle. The force will remain normal to the surface it is
applied to. Evaluate the observed changes in maximum stress in the joint