The shear formula in Solid Mechanics I (τ = VQ/It) is useful as it helps us to find the critical τ_{max}, which would help us to design a safe structure that can withstand the τ_{max}.
The shear flow q is another shear loading quantity that is useful for design purposes. It measures the shear force per unit length and is useful in applications of:
The shear formula in Solid Mechanics I (τ = VQ/It) is useful as it helps us to find the critical τ_{max}, which would help us to design a safe structure that can withstand the τ_{max}.
The shear flow q is another shear loading quantity that is useful for design purposes. It measures the shear force per unit length and is useful in applications of:
Without further ado, let’s look at the formula:
Another information of interest is how the shear actually “flows” in the cross-section. Knowing where the shear flow starts and ends will help us determine how we calculate our “Q” (Q = Aȳ) at the point of interest.
Here are two useful hints to help us determine our shear flow direction:
Putting these 2 guidelines together, here are the shear flow distributions of some common cross-sections:
At the point where q starts in the cross-section, q = 0, but as it flows q gradually increases because Q = Aȳ goes up as well. An example of the q magnitude distribution for an I-section is shown below:
Using this information, we can actually work out the force caused by the shear flow for an arbitrary segment of the cross-section:
This might look difficult, but we’ll be looking at an example of this later in Question 3. For now, let’s look at a simple example.
Without further ado, let’s look at the formula:
Another information of interest is how the shear actually “flows” in the cross-section. Knowing where the shear flow starts and ends will help us determine how we calculate our “Q” (Q = Aȳ) at the point of interest.
Here are two useful hints to help us determine our shear flow direction:
Putting these 2 guidelines together, here are the shear flow distributions of some common cross-sections:
At the point where q starts in the cross-section, q = 0, but as it flows q gradually increases because Q = Aȳ goes up as well. An example of the q magnitude distribution for an I-section is shown below:
Using this information, we can actually work out the force caused by the shear flow for an arbitrary segment of the cross-section:
This might look difficult, but we’ll be looking at an example of this later in Question 3. For now, let’s look at a simple example.