# Manually Attempting Empirical Measurement of Flour Dough Compressive Strength

I want to make a DIY dough press, so need to know how much pressure I would need to apply. I don't have mechanical engg background, so based on some googling, I think this is what I need to do, but wanted to validate here.

I took a small dough ball, and placed a very light flat surface on its top, and then put a 16.9 fl oz water bottle (weighing 1.1 lbs) on top of it. It squished the dough ball to a thick circle of 2.09 inch diameter. (3.145 sq inch area).

Then I put 7 more water bottles on top of it (total 8.8 lbs approx), and the dough squished flatter to a circle of 2.91 inch (6.647 sq inch).

Now my questions are,

a) Is this correct way to calculate compressive strength of this dough ball by dividing force / area, where it came to rest. So with 1 bottle on top, when it squished somewhat flatter, the PSI = 1.1/3.145 = 0.349 lbs/sq inch

b) If so, then shouldn't the compressive strength be constant as it is tied to the material. So dividing the final area after adding more weight should yield the same value? The second value, 8.8/6.647 = 1.323 lbs/sq inch.

Assume you were able to put uniform pressure each time on the dough, and assume the material property is uniform in all directions, then it is correct that the stress readings should be $$W_1/A_1$$ and $$W_2/A_2$$. However, the stresses will not be constant, unless $$A_2 = 8*A_1$$ (for $$W_2 = 8*W_1$$).
In reality, the stresses will not uniform due to change in strains ($$Strain = \frac {\Delta L}{L}$$) as shown on the stress-strain curve below.