For reliability prediction and analysis you should also define the environment and temperature of product tree assemblies and components.

 

Product environment and temperature should be defined on the top item data screen - see paragraph Top item definition.

 

All underlying components and assemblies in the product tree inherit their environment and temperature settings from higher level items, if their Environment is set to "---" and temperature is set to Delta=0 (in red):

Parent item has environment=GF and temperature = 35, this assembly has default (---) environment and no temperature raise (Delta=0) so its current conditions ar GF and 35 degrees too (in green).

You do not need to set or change environment or temperature of items if they are the same as for their parent items.

 

If environment of some assembly differs from parent items, change it's Environment (see Standard Environments ).

 

If temperature of some assembly differs from parent items, there are two options:

Select "Delta temp" and set the difference if there is some relative temperature change on some assembly. In example below we have 5 degrees temperature raise, from 35 degrees of parent assembly to 40 degrees on current assembly:

Please note that if parent assembly temperature will be changed, the temperature of this sample assembly (and all its sub-levels) will be recalculated automatically, keeping the relative raise of 5 degrees.

Select "Fixed temp" and set the fixed temperature on assembly if you have some block with controlled constant temperature which does not depend on whole product's operating temperature (for example, aircraft operating at -50 degrees but having cockpit temperature +15 degrees).

In example below we have fixed temperature of 15 degrees set for some assembly which parent assembly has temperature of 35 degrees:

 

See several product tree examples for one more illustration of this concept:

In the first image top item temperature is set to 35:

Then it is changed to 20 degrees:

Pay attention to temperature change (keeping relative deltas) of items with "delta" temperature settings and no change for items with "fixed" temperature settings.