Wagner Bros plans to build a new warehouse near Sidney, Australia, in order to supply its sales points in New South Wales. On the basis of a preliminary analysis of the problem, it has been decided that the facility should accommodate at least 780 pallets of 90 x 90 cm dimension. The pallets will be stored onto conventional racks and transported by means of reach trucks. Each rack has four shelves, each of which can store a single pallet. Each occupies a 1.05 x 1.05 area. Racks are arranged as in the figure below, where side aisles are 3.5m wide, while the central aisle is 4m wide. The average speed of a reach truck is 5km/h. What is the optimal dimensions of the storage that minimizes average order picking time?
Can you solve according to:
Lx = Length of the storage area
Ly = Width of the storage are
nz = Number of storage locations on z direction
m = number of required storage locations
ax = occupation of unit load on direction x
ay = occupation of unit load on direction y
wx = width of the side aisles
wy = width of the center aisles
v = average speed of the picker
nx = Number of storage locations along x direction
ny = Number of storage locations along y direction
