New answers tagged

0

Let's call the length of the handle from the center,D, and the OD of the ring R. mass of the rod if it continued to center,m and mass of the ring m(r) $F*D=\frac{1}{3}m(D^2-(R/D)^2)+m_rR^2$ What we have done here is assumed the ring is thin and all its mass is at distance R. calculated the moment of inertia of the bar by assuming it continues to the center, ...


1

If your question is : how should be the force distribution at the cross section right before the fixed support? This was my actual question, actually. Since the structure needs to transfer internally a bending moment right before the support there will be a tension layer and a compression layer. The combination of those layers in each cross-section is that ...


1

The stresses will be dense at the support and gradually fanned out per the elastic property of the material of the beam. Theory of Elastic Plate, or the finite method, is required to find the exact/approximate distribution width ($b_{EFF}$) alone the X-Axis.


1

We could think of the second case as a beam welded to the support only on the top part as you show say with a length H/4, with the beam length L, and its height, H, the shear substituted with a point load P. The weld has to support the entire shear,$ \ P$, and a tensile force equal to the tensile force that is required to resist the moment of PL. $$T=C =\...


-1

Response of the follower to a cam curve command creates two types of vibrations. A steady-state vibration. A transient type of vibration. These vibrations should be designed not to be close to the natural frequency of the camshaft or connecting mechanism. source


-1

For car engines, the max rpm can be limited by what is known as valve bounce. This is where the valve fails to keep up with the cam profile then either hits the cam or cam follower or the valve seat and bounces back. There have been designs like sleeve valves or desmodromic valves to avoid this but expense comes into the equation.


1

This is a long answer because I need to cover a lot of things. IF something is doesn't make sense let me know. What are those diagrams The Modified Goodman and the Smith diagram (and others) are diagrams that hope to predict the life of a material under fatigue loading. types of Fatigue loading The problem with fatigue loading is that it is not defined in a ...


1

They are not the same. here is a chart comparing various methods and the equations used to model them. source '


0

Both of them potentially give accurate results. The accuracy of the results depends mainly on the application and the correct use. As a general rule Surface meshes are usually more appropriate with sheets of metals. (the width and length have values that are much greater than the thickness). Solid meshes are usually more appropriate for parts that all the ...


4

Modern building failure due to tipping is rare but did occur, usually under strong earthquakes and loss of foundation (soil and structure), as the tilt will shift the gravity center of the building that induce a tremendous amount of stress on the foundation piling and the soil mass surrounding the piling. So, how much is too much for a building to handle (...


1

Engineering point of view: There are ropes that do have significant bending stiffness (and, as a consequence, compression hardness). E.g. steel wire ropes. This is almost never an advantage - such ropes tend to self-tangle easier (but making intentional knots is harder), tend to break at small bending radius (making most knots unusable) and tend to retain ...


2

"$E$", "$K$", and "hardness", all indicate stiffness but are measured and used in different manners. $E$ - Elastic modulus is defined as the slope of the tangent line to the stress-strain (elastic) curve. It is a material-specific quantity that measures the resistance to being deformed elastically when stress is applied to it, ...


1

Check out this link, it might help. Should we use Hooke's Law (that linearly relates stresses to strains) if the stiffness of body is changing during deformation? Now, the stiffness equation i.e. K = EA/L is only used for axial loading conditions. It is derived by dividing the load applied by max deflection. However, for bending cases, the bending stiffness ...


2

(Spring) Stiffness $K$ is a property of a structure which includes geometric and material effects. On the other hand, Young's Modulus $E$ is a property of the material. Bottom line is that given the same material (i.e. same Young's modulus), changing the cross-section A or the length L could result in different deformation. So: for a given structure K is ...


3

Having low stiffness is part of the specification of a rope. It would be far cheaper to obtain the same tensile strength with a solid rod. Creating and manipulating multiple strands is expensive. It is designed to use multiple thin strands to achieve this lack of stiffness. The question of how thin strands, with their small moment of area, achieve this lack ...


2

It won't just keep itself straight You know a steel beam held at one end won't just keep itself straight either right? It also bends under it's own weight when supported by one end. Just because you can't perceive something with eyes doesn't mean it's not there. It just means your eyes aren't precise enough. The fact that the rope has a radius of curvature ...


1

They design the jumping rope this way. if it would have any moment strength or compression strength it woul act as a soft "column" at the strat where half of the cord is bent up to reach the Jumper's harness. Thus it could send the jumper into an unpredictable dangerous arc, as opposed to let them fall straight down into hopefully a clear vertical ...


17

TL;DR: The bending and compression (buckling) stiffness is so small because the second moment of area of the fibres is small. Bending stiffness It does have a bending stiffness however it is really really small. More precisely it has a really really small second moment of area per fibre. (see the numerical example below to understand why many more ...


0

I think all the DIN standards are now ISO. Here are references I found: Corresponding ISO standard, primary source -- ISO 898-1:2013 PDF copy of ISO 898-1:2013 from google search To indirectly address the OP question, see document sections 6 (Materials), and 7 (Mechanical Properties). The document specifies a a bunch of of properties like strength and ...


Top 50 recent answers are included