Calculations

Terms Used:
Length in mm (L):
Width in mm (W):
Height in mm (H):
Thickness in mm (t):
Water Pressure (p):
Allowed Bending Stress (B):
Modulus of Elasticity (E):

The length of the aquarium.
The width of the aquarium from front to back.
The overall depth of water that is in contact with the glass, but does not exceed its upper edge.
The thickness of the Glass.
The force in Newton’s (N).
Tensile Strength / Safety Factor
Elastic Strength

The length to height ratio effects the strength of the glass. The table below lists alpha and beta constants to be used based on with the length to height ratio.

Table of Alpha and Beta Constants used in the Caculations

Ratio of Length to Height (L/H)
0.5
0.666
1.0
1.5
2.0
2.5
3.0

For Side Panels
Alpha
0.003
0.0085
0.022
0.042
0.056
0.063
0.067

Beta
0.085
0.1156
0.16
0.26
0.32
0.35
0.37

For Bottom Panels
Alpha

0.077
0.0906
0.1017
0.111
0.1335

Beta

0.453
0.5172
0.5688
0.6102
0.7134

When the ratio is less than 0.5, use Alpha and Beta values for 0.5.
When the ration is greater than 3, use Alpha and Beta values for 3.
Note: For bottom panel, use Length to Width ration (L/W).

The water pressure (p) is directly proportional to the Height (H) x the force of gravity
(approx 10 (9.81 for people who want to be exact)).

p = H x 10 in N/mm2

The bending stress allowed (B) is equal to the Tensile Strength of glass / safety factor.
B = 19.2 / 3.8 = 5.05N/mm2 (Safety factor = 3.8)

Next - Calculations for front and sides