What does a Southwell plot tell us about column imperfections?
In: Mechanical Engineering
How do you solve this?
A thin-wall pressure vessel is shown below. Internal diameter=d, wall thickness=t.
In addition to the internal pressure p (p=100 psi), a torque T is applied. Assume d=20 inch (r=10 in), t=0.1 inch, T=502,640 in-lb. Determine the wall stress components. Assume that the longitudinal direction is labeled as x and the circumferential (hoop) direction is label as y.
Use Mohr's circle to determine the principle strains and maximum shear strain. Assume that E=10,000 ksi and Poisson's ratio v=0.3 and plane stress case.
Find epsilon x, y, and z. Find gamma xy
In: Mechanical Engineering
he path of motion of a 7-lb particle in the horizontal plane is described in terms of polar coordinates as r = (3 t + 1)ft and θ = (0.5 t2 − t) rad, where t is in seconds.Determine the magnitude of the unbalance force at t = 3.0 seconds.
In: Mechanical Engineering
Thermodynamics: You have a (mostly) insulated carafe in which you store your coffee. Coffee can be modeled as saturated water for this problem. The internal volume of your carafe is 1 L and you seal the lid when it contains 900 g of coffee (mostly liquid, some vapor) at 90 ◦C.
1. What is the mass [g] of water vapor in the carafe?
You are very busy at work and forget to drink your coffee. By the end of the day, it has cooled to 35 ◦C.
2. How much energy [kJ] was lost through the walls of the carafe?
3. What is the pressure [kPa] of your now barely warm coffee?
In: Mechanical Engineering
Material Science question
Rank the following elements with regard to how rapidly they will diffuse into FCC Iron (fastest to slowest). Indicate the diffusion mechanism for each.
1) Mo
2) C
3) Cr
4) W
In: Mechanical Engineering
A circular shaft, 100 mm diameter is subjected to combined
bending moment and torque, the bending moment being 3 times the
torque. If the direct tension yield point of the material is 300
MN/m2 and the factor of safety on yield is to be 4, calculate the
allowable twisting moment by the three following theories of
failure:
(a) Maximum principal stress theory
(b) Maximum shear stress theory
(c) Maximum shear strain energy theory.
In: Mechanical Engineering
Explain the following observations, using diagrams to illustrate your answer wherever possible:
(a) Steel nails used to hold copper roofing sheet in position failed rapidly by wet corrosion.
(b) The corrosion of an underground steel pipeline was greatly reduced when the pipeline was connected to a buried bar of magnesium alloy.
(c) Mild-steel radiators in a central heating system were found
to have undergone little corrosion after several years'
service.
(d) A reaction vessel for a chemical plant was fabricated by
welding together stainless steel plates containing 18% chromium, 8%
nickel and 0.1% carbon. During service, it was observed that the
vessel corroded badly near the welds.
In: Mechanical Engineering
A five metre tall, 1 m diameter Flettner rotor mounted on a small cargo vessel, spins at 50 rpm in a steady beam breeze of 15 knots. What is the thrust generated by the rotor? The air density and viscosity may be assumed constant at 1.22 kg/m3 and 1.79 x 10‐5 Pa.s respectively. Note also that 1 knot = 0.514 m/s. Which direction must the rotor spin to produce forward thrust?
In: Mechanical Engineering
Describe a typical polymer molecule in terms of its chain structure and repeat units. Use a specific example polymer other than polyethylene to illustrate the ideas
In: Mechanical Engineering
The origins of stiffness
Explain the relationship between the cohesive energy of bonding and the observed stiffness of individual bonds.
How does the stiffness of individual bonds in a solid affect the overall stiffness and elastic modulus of the material?
What is the atomic level mechanism of elastic deformation? In other words, what is occurring within a solid when it is elastically deformed?
In: Mechanical Engineering
(Amorphous vs semi-crystalline)
Using words and visuals, describe the amorphous and semi-crystalline arrangements of polymer chains when forming a solid. Using examples of specific polymers, explain why some types of polymer chains do not readily align and tend to be amorphous while others readily form semi-crystalline structures.
In: Mechanical Engineering
Describe a future innovation that you envision may occur during your Mechanical Engineering career (next 40 years), and what your engineering role would be in its development and/or production?
In: Mechanical Engineering
A signal has the functional form f(t) = 5sin(40πt) and is sampled at a rate of 30 samples per second. What false alias frequency would you expect in the discrete data? What sampling rate would avoid aliasing this signal?
In: Mechanical Engineering
A railway buffer consists of a pair of cylinders placed parallel side-by-side. Oil is present in each cylinder and is arranged to bypass through ports, thereby producing a damping resistance, which is proportional to the velocity of the piston within the cylinder. The magnitude of this resistance is 50 kN at a velocity of 0.25 m/s. Each cylinder also contains a compression spring, initially with negligible compression, of stiffness 65 kN/m. A rigid train of mass 250 tons is moving at a speed of 1.6 m/s and collides with the buffer. Determine the distance taken by the train before first coming to rest. Assuming that the train comes into contact and then become attached to the free end of the buffer. Determine the time it takes the train to come to a complete stop. Solution for this problem should show the position and velocity of the train.
In: Mechanical Engineering
What happens to an inventor within an organization,whose invention is not successfully commercialized? Have you seen examples?
In: Mechanical Engineering