65 lines
1.9 KiB
Python
65 lines
1.9 KiB
Python
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"""
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Extract von Mises stress from CHEXA elements
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Auto-generated by Atomizer Phase 3 - pyNastran Research Agent
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Pattern: solid_stress
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Element Type: CTETRA
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Result Type: stress
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API: model.ctetra_stress[subcase] or model.chexa_stress[subcase]
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"""
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from pathlib import Path
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from typing import Dict, Any
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import numpy as np
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from pyNastran.op2.op2 import OP2
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def extract_solid_stress(op2_file: Path, subcase: int = 1, element_type: str = 'ctetra'):
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"""Extract stress from solid elements."""
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from pyNastran.op2.op2 import OP2
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import numpy as np
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model = OP2()
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model.read_op2(str(op2_file))
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# Get stress object for element type
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# In pyNastran, stress is stored in model.op2_results.stress
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stress_attr = f"{element_type}_stress"
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if not hasattr(model, 'op2_results') or not hasattr(model.op2_results, 'stress'):
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raise ValueError(f"No stress results in OP2")
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stress_obj = model.op2_results.stress
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if not hasattr(stress_obj, stress_attr):
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raise ValueError(f"No {element_type} stress results in OP2")
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stress = getattr(stress_obj, stress_attr)[subcase]
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itime = 0
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# Extract von Mises if available
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if stress.is_von_mises: # Property, not method
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von_mises = stress.data[itime, :, 9] # Column 9 is von Mises
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max_stress = float(np.max(von_mises))
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# Get element info
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element_ids = [eid for (eid, node) in stress.element_node]
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max_stress_elem = element_ids[np.argmax(von_mises)]
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return {
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'max_von_mises': max_stress,
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'max_stress_element': int(max_stress_elem)
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}
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else:
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raise ValueError("von Mises stress not available")
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if __name__ == '__main__':
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# Example usage
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import sys
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if len(sys.argv) > 1:
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op2_file = Path(sys.argv[1])
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result = extract_solid_stress(op2_file)
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print(f"Extraction result: {result}")
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else:
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print("Usage: python {sys.argv[0]} <op2_file>")
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