v2.01.033 SDLD33 - Spectral seismic response of a 2-mass system - 4 springs multi-supported by 2 uncorrelated support groups

Summary:

The problem consists in calculating the spectral response of a 2 mass—4 multi-supported spring system, subjected to multiple seismic excitation, by considering the 3 supports as 2 uncorrelated support groups.

We test the discrete element in traction, the calculation of the natural modes, the static modes and the spectral response by modal superposition via the operator COMB_SISM_MODAL.

Modeling A: this modeling makes it possible to validate the order of the combinations to be considered in the case of the multi-support system, namely intra-group accumulation then inter-group accumulation.

B modeling: this modeling makes it possible to validate the combination rules to be considered in the accumulation of decorrelated support groups with DDS equal intra-group.

C modeling: this modeling makes it possible to validate output options for spectral modal calculations in case of correlated multi-support.

The results obtained are in very good agreement with the reference analytical results.

• 1. Reference problem
  • 1.1. Geometry
  • 1.2. Material properties
  • 1.3. Boundary conditions and loads
  • 1.4. Initial conditions
• 2. Benchmark solution
  • 2.1. Calculation method used for the reference solution
  • 2.2. Benchmark results
  • 2.3. Uncertainty about the solution
• 3. Modeling
  • 3.1. Characteristics of the mesh
  • 3.2. Characteristics of modeling
  • 3.3. Modeling parameters
• 4. Model A results
  • 4.1. Natural frequencies
  • 4.2. Global response on a full modal basis
• 5. B modeling results
  • 5.1. Calculation 1: Combining decorrelated support groups with DDS equal intra-group
  • 5.2. Calculation 2: Intra-group and inter-group linear combination
  • 5.3. Calculation 3: Intra-group and inter-group quadratic combination
• 6. C modeling results
  • 6.1. Total response in case of correlated multi-support TYPE_RESU (_F (TYPE = VALE_TOTA)).
  • 6.2. Spectral response TYPE_RESU (_F (TYPE = VALE_SPEC)).
• 7. Summary of results