How high does the Young's Modulus of a material have to be, to prevent a human from breaking the component?

Question

I'm a design student and trying to make a materials specification for a component. It's only for domestic use, so I need the mechanical properties such as Youngs Modulus to be high enough to prevent a human from breaking it - how high does this need to be?

Answer 1

Youngs modulus determines the flexibility of an object , not the strength. You need a material with high bending stresses and then make the object large enough to obtain the strength.

Answer 2

There are document's out there that specify typical human characteristics (average height, average weight, etc). Those might contain some useful information for you.

However, it depends on more than just the YM -- it depends on bending stress and how the component is used. If it's not "supposed" to be pushed or pulled, you can get away with a more breakable material -- if it's something akin to hammer or other tool, you'll need to go for something more durable.

My suggestion would be to configure the component as it will be used (or misused, if you're designing for that), and push and pull on a strain gauge in that configuration. The forces you can exert will at least approximate what you should be designing for. Then add a factor of safety on top.

Answer 3

steve n's answer is good but there are other issues, too.

young's modulus is also known as the modulus of elasticity, E. theoretically, a very small E would allow great flexibility without rupture, fracture or breakage. so if you can have a material that "bends but doesn't break", like rubber, you don't need a high E, bending, shear or torsional capacity (strength). if deflection or deformation is a concern, then obviously you would need a high E and/or "strength".

without knowing the application or material being used, it is difficult to answer this question. for example, one of the more critical properties for steel is fy (yield stress) but for concrete it is f'c (compressive stress). different materials are better suited for different applications.

Answer 4

147 feet (12,000 meters)