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It must surely be the F in the diagram. This is shared over two bolts each side, so I expect to see F/2 in the equations. And indeed that is what we do see.minoroctave said:I am having trouble understanding the F used in these equations. Is it supposed to be the force F shown on the left, or is it F/2 or F/4?
haruspex said:It must surely be the F in the diagram. This is shared over two bolts each side, so I expect to see F/2 in the equations. And indeed that is what we do see.
I'm saying each bolt gets F/2, but I can't comment beyond that without knowing what t and d represent.minoroctave said:So each bolt get F/4 and that's why the bearing stress equations are
##\frac{\frac{F}{4}}{\frac{t}{2} d} = \frac{F}{2td}##
?
haruspex said:I'm saying each bolt gets F/2, but I can't comment beyond that without knowing what t and d represent.
Ok,then it is the same F as in the diagram. Each bolt takes half the load, F/2. To get the bearing stress, divide by the area, td.minoroctave said:for the bearing stress equations, d is supposed to be the bolts major diameter and t is the thickness of the thinnest plate
but according to the definition they gave, shouldn't t be the thickness of the thinnest plate. in the question, its also mentioned that:haruspex said:Ok,then it is the same F as in the diagram. Each bolt takes half the load, F/2. To get the bearing stress, divide by the area, td.
To get the shear stress, you have to consider that there are two shear planes for each bolt, one at each side of the central plate (so distance t apart). Each of those has a shear force F/4, and an area πd2/4.
Sorry, can't decipher the meaning of that.minoroctave said:but since the areas of the splice plates are half those of the center bars, the stresses associated with the plates are the same. So for stresses associated with the plates, the force and areas used will be those of the center plate
How do you mean only in that question? At the shear planes as opposed to, where else?minoroctave said:is the shear force a max of F/4 only at these shear planes?
as opposed to anywhere else between the bolt head and the nutharuspex said:Sorry, can't decipher the meaning of that.
How do you mean only in that question? At the shear planes as opposed to, where else?
There is no other shear plane between those.minoroctave said:as opposed to anywhere else between the bolt head and the nut
haruspex said:There is no other shear plane between those.
I'll get this right in a minute...minoroctave said:so shear only exists at the shear planes? doesn't it vary between the planes like this:
http://postimg.org/image/3z13rz8kj/
haruspex said:I'll get this right in a minute...
There are two shear planes at each bolt, but they are not adjacent to the head or nut. The shear planes are where the bolt passes from one plate to another.
You are dividing by 4 twice over.minoroctave said:for the shear equations, it says the area is supposed to be the total cross sectional area of all the bolts in the group. So since each of the shear planes has a shear force F/4, and an area πd2/4 and since there are four bolts,
so ## \frac{\frac{F}{4}}{4 ( \pi \frac{d^2}{4})} ## = ##\frac{F}{4 \pi d^2}##
but that doesn't agree with the equation in the image
haruspex said:You are dividing by 4 twice over.
You can think of it in many different ways:
- a total force of F spread over four (half) bolts with a total area of πd2
- a force of F/2 on each of two bolts, each with a shear plane area of πd2/2
- a force of F/4 on each of four shear planes, each with an area of πd2/4
All lead to the same answer.
A bolted joint loaded in shear is a type of mechanical connection where two or more parts are joined together using bolts. The bolts are loaded in a direction parallel to the joint surface, causing the parts to be held together by friction and shear forces.
Bolted joints loaded in shear differ from other types of joints, such as welded or riveted joints, in that they can be easily disassembled and reassembled without damaging the parts. They also allow for more flexibility in design and provide a more uniform distribution of stress.
The strength of bolted joints loaded in shear can be affected by several factors, including the type and grade of the bolts used, the size and number of bolts, the material and surface finish of the parts being joined, and the amount of preload applied to the bolts. Proper installation and maintenance also play a crucial role in the strength of these joints.
Bolted joints loaded in shear offer several advantages, including ease of assembly and disassembly, flexibility in design, and the ability to handle high loads and vibrations. They also allow for adjustments and replacements to be made without damaging the parts, making them a cost-effective option for many applications.
While bolted joints loaded in shear are suitable for many applications, there are some limitations and considerations to keep in mind. These include the potential for loosening due to vibrations or external forces, the need for proper tightening and maintenance, and the possibility of corrosion if the joint is exposed to harsh environments. Additionally, the strength of the joint may decrease over time due to fatigue and creep.