Environments
For the calculation models listed in the following table, the environment in which the system operates has a considerable effect on prediction results. Because environment choices vary from model to model, you should scrutinize the environments supported by models prior to deciding which to use. For example, Telcordia models do not support naval environments. Consequently, it would not be the model of choice for a system that operates on a naval ship. In the referenced topics, both the environments supported by a model and the codes assigned to environments are listed.
Model
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Reference
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MIL-HDBK-217, Telcordia, and Bellcore
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299C and 299B
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217 Plus and PRISM
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217 Plus Parts Count
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HRD5
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Mechanical
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The FIDES, IEC TR 62380, RDF 2000, and Siemens models do not use environments but rather mission phase and/or cycling information that are provided in the Prediction support files for these methodologies. For more information, see Prediction Support Files.
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When a model that supports environments is selected in an assembly’s Calculation Data pane, Environment and possibly Environment, dormant are shown. In the field name for Environment, the one or more models whose environments are included in the attached list are shown. For example, when a MIL-HDBK-217, Telcordia, or Bellcore model is selected, Environment, 217 / Telcordia is the field name. For these models, choices for Environment, dormant are: Airborne, Ground, Naval, and Space.
MIL-HDBK-217, Telcordia, Bellcore, 299, and HRD5 models support custom environments. You can insert custom environments that you want to use for these models in
Prediction Values Library files. For more information, see
Prediction Values Library Files. Additionally, you can insert a custom environment from a
System file by directly entering it for Environment in the
Calculation Data pane for an assembly. For more information, see
Inserting a Custom Environment or Quality Level from the System File.