Can I calculate modal mass and Kinetic Energy for modal analysis using DPF?
Oscar
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In MAPDL, the solver output prints a table with Modal Mass and Kinetic Energy per mode calculated with Unit Normalized modes. Can we get the same type of result from Mass Normalized modes using DPF for situations where this output is not available in MAPDL (cyclic, multistage?
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Here's un example on how to calculate it from modal analysis results using DPF:
import mech_dpf import Ans.DataProcessing as dpf mech_dpf.setExtAPI(ExtAPI) analysis = Model.Analyses[1] dataSource = dpf.DataSources(analysis.ResultFileName) tfs_op = dpf.operators.metadata.time_freq_provider() tfs_op.inputs.data_sources.Connect(dataSource) tfs = tfs_op.outputs.time_freq_support.GetData() freqs = tfs.TimeFreqs.Data u_op = dpf.operators.result.displacement() u_op.inputs.data_sources.Connect(dataSource) u_op.inputs.bool_rotate_to_global.Connect(False) u_op.inputs.read_cyclic.Connect(2) # If cyclic expansion needed print("MODE","FREQUENCY","MODAL MASS","KENE") for i in range(len(freqs)): u_op.inputs.time_scoping.Connect([i+1]) U_Mass_normalized = u_op.outputs.fields_container.GetData()[0] max_comp_op = dpf.operators.min_max.min_max_inc() max_comp_op.inputs.field.Connect(U_Mass_normalized) max_comp = max_comp_op.outputs.field_max.GetData() min_comp = max_comp_op.outputs.field_min.GetData() modal_mass = 1/max(max_comp.Data[0], max_comp.Data[1], max_comp.Data[2], abs(min_comp.Data[0]), abs(min_comp.Data[1]), abs(min_comp.Data[2]))**2 KE = 1/2*modal_mass*(freqs[i]*2*acos(-1))**2 print(i+1, freqs[i], modal_mass, KE)
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