How Do You Calculate the Maximum Axial Compressive Load for a Steel Punch?

[eddyb]

I have a question on axial loads. I can get to a certain point but can't quite work out how to used the forumla properly. The question is

Given that the maximum compressive stress for steel is 235MN/m2. Using a factor of saftey of 3, determin the maximum axial compressive load that can be applied to a steel punch with a 25mm circumferance.

So far i work out we need to find the area of the punch, which we work out diameter first then half it and work out area using pie x r squared. This is fairly easy but now i know the forumla to use but do i need to work out the slenderness ratio first?

cheers

 

[andrevdh]

I think you should keep it simple:

With a safety factor of 3 the maximum compressive stress that should be applied to the punch is 78.3 MN/m^2. The maximum load that it should experience can be calculated by using the cross sectional area that you calculated.

 

[kyle8921]

I can provide some guidance on how to approach this problem. First, let's define some terms. Stress is a measure of the internal force per unit area in a material, while strain is a measure of the deformation or change in length of a material due to stress. In the case of steel, stress and strain are related by the material's elastic modulus, which is a constant that describes the material's stiffness.

Now, let's apply this to the problem at hand. We are given the maximum compressive stress for steel, which is 235MN/m2. This means that if we were to apply a compressive force to a steel object, the maximum stress it can withstand before it starts to deform is 235MN/m2. We also have a factor of safety of 3, which means that we need to divide the maximum stress by 3 to ensure that we are not exceeding the material's capacity.

Next, we need to determine the maximum axial compressive load that can be applied to a steel punch with a 25mm circumference. To do this, we need to find the area of the punch. As you correctly pointed out, we can do this by using the formula for the area of a circle (pi x r2), where r is the radius of the punch. However, we also need to take into account the slenderness ratio, which is the ratio of the length of the punch to its cross-sectional area. This is because long and slender objects are more susceptible to buckling under compressive loads.

To find the slenderness ratio, we need to divide the length of the punch by its diameter, which we can calculate from the given circumference (circumference = 2 x pi x r). Once we have the slenderness ratio, we can use it to determine the maximum axial compressive load that the punch can withstand. This can be done by multiplying the area of the punch by the maximum stress and dividing it by the slenderness ratio and the factor of safety.

In summary, to solve this problem, we need to find the area of the punch, calculate the slenderness ratio, and then use these values to determine the maximum axial compressive load. I hope this helps and good luck with your calculations!