EXPAND
EXPAND
Description 
Expands the Node by the desired Levels. The result is a cross product of all rows of the Node with all values of the Level entered in the formula. 
Signature 
EXPAND(Node, Level1 [, Level2, …]) 
Parameters 

Examples
Input =
Value 

1.1 
EXPAND('Input',"Year") =
Year  Value 

2017  1.1 
2018  1.1 
2019  1.1 
...  1.1 
EXPAND('Input',"Year","Product") =
Year  Product  Value 

2017  A  1.1 
2017  B  1.1 
2018  A  1.1 
2018  B 
1.1 
...  A  1.1 
...  ...  1.1 
Use Case
We want to add delivery costs to our Variable Costs per product, but the granularity of the delivery costs are define at higher level.
Delivery Costs =
Product Line  Delivery Costs 
M  100 
Z  200 
Variable Costs w/o Delivery =
Product Line  Product  Variable Costs 

M  M1  750 
M2  2250  
Z  Z3  3000 
ADDITION (+) with NonOverlapping Dimensions leads to loss of the product dimension with delivery fee added only once.
'Delivery costs' + 'Variable Costs w/o Delivery' =
Product Line  OPEX 
M  750 + 2250 + 100 = 3100 
Z  3000 + 200 = 3200 
Using expand, the delivery costs are expanded to the product level and we get the expected result.
EXPAND('Delivery Costs',"Product") + 'Variable Costs w/o Delivery' =
Product Line  Product  Totals 

M  M1  750 + 100 = 850 
M2  2250 + 100 = 2350  
Z  Z3  3000 + 200 = 3200 
If you need only one single value, take a look at EXPANDSINGLE.