REG NASA-LLIS-1223--1998 Lessons Learned Limitations of extended use of simplified modeling.pdf

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1、Lessons Learned Entry: 1223Lesson Info:a71 Lesson Number: 1223a71 Lesson Date: 1998-10-20a71 Submitting Organization: JSCa71 Submitted by: Mark Mulqueen/ Ronald A. MontagueSubject: Limitations of extended use of simplified modeling Description of Driving Event: The basis of the Z1 ITS modeling strat

2、egy in the preliminary and conceptual design phases was a simplified beam element representation of the primary structure bulkheads and panels. This facilitated rapid, automated beam based stress analysis of the primary structure and decreased the design cycle time as well as manpower loading. The s

3、ame model was used for both (1) the design dynamic-coupled load analysis and (2) the pre-test model and static test prediction analyses.The pretest model analysis model produced poor correlation with the model test data. The correlation was improved by remodeling critical bulkheads and panels in gre

4、ater detail using shell elements for the basic web and shell/beam elements for the upstanding ribs & flanges. Solid elements were also used where “plate“ proportions did not exist. The increased fidelity of the post-test model led to improved correlation with the static test as well. However, the ch

5、anges made to the model have forced a re-evaluation of the internal stresses both because of the change in model response and/or load paths. This re-evaluation came long after the design of the hardware was finalized and manufacturing completed. Any adverse findings from this re-evaluation could lea

6、d to costly retrofits or undesired limitations on hardware use during operations.Lesson(s) Learned: Use of models must be refined as design matures to ensure fidelity of analyses of the final designRecommendation(s): Use simplified models of the structure as appropriate during early design work but

7、switch to higher fidelity models when the design is fairly mature before going into the final analysis and verification phases. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Less

8、on: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Computer-Aided Design/Manufacturing/Engineeringa71 Flight Equipmenta71 Ground Equipmenta71 Hardwarea71 Independent Verification and Validationa71 Policy & Planninga71 Risk Management/Assessmenta71 Safety & Mission Assurancea71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 2002-06-27a71 Approval Name: Ronald A. Montaguea71 Approval Organization: JSCa71 Approval Phone Number: 281-483-8576Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-