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4 years ago

Describe the "Bauschinger Effect" on the stress strain behaviour of steel

Engineering

1 answer:

Rom4ik [11]4 years ago

7 0

Answer:

The Bauschinger effect is the directionally determined change in the elasticity limit of a metal or alloy after primary plastic deformation. If you first deform a metal in one direction so that it is plastically deformed and then deform it in the opposite direction, the elastic limit in the opposite direction is lower.

From the point of view of the dislocation mechanism of plastic deformation, the Bauschinger effect indicates that during repeated deformation, it is easier for dislocations blocked in front of obstacles to move in the direction opposite to their movement during preliminary plastic deformation.

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2.11 Consider a 400 mm × 400 mm window in an aircraft. For a temperature difference of 90°C from the inner to the outer surface

alexandr402 [8]

Answer:

The heat loss rate through one of the windows made of polycarbonate is 252W. If the window is made of aerogel, the heat loss rate is 16.8W. If the window is made of soda-lime glass, the heat loss rate is 1190.4W.

The cost associated with the heat loss through the windows for an 8-hour flight is:

For aerogel windows: $17.472 (most efficient)

For polycarbonate windows: $262.08

For soda-lime glass windows: $1,238.016 (least efficient)

Explanation:

To calculate the heat loss rate through the window, we can use a model of heat transmission by conduction throw flat wall. Using unidimensional Fourier law:

$\frac{dQ}{dt}=\dot Q =-kS\nabla \vec{T}$

In this case:

$\dot Q =k\frac{S}{L} \Delta T$

If we replace the data provided by the problem we get the heat loss rate through one of the windows of each material (we only have to change the thermal conductivities).

To obtain the thermal conductivity of the soda-lime glass we use the graphic attached to this answer (In this case for soda-lime glass k₃₀₀=0.992w/m·K).

To calculate the cost associated with the heat loss through the windows for an 8-hour flight we use this formula (using the heat loss rate calculated in each case):

$Cost=C_{hc}\cdot \dot Q \cdot t \cdot n=1\frac{\$}{Kwh} \cdot \dot Q \cdot 8h \cdot 130$

6 0

3 years ago

The pressure distribution over a section of a two-dimensional wing at 4 degrees of incidence may be approximated as follows: Upp

Aliun [14]

Answer:

The lift coefficient is 0.3192 while that of the moment about the leading edge is-0.1306.

Explanation:

The Upper Surface Cp is given as

$Cp_u=-0.8 *0.6 +0.1 \int\limits^1_{0.6} \, dx =-0.8*0.6+0.4*0.1$

The Lower Surface Cp is given as

$Cp_l=-0.4 *0.6 +0.1 \int\limits^1_{0.6} \, dx =-0.4*0.6+0.4*0.1$

The difference of the Cp over the airfoil is given as

$\Delta Cp=Cp_l-Cp_u\\\Delta Cp=-0.4*0.6+0.4*0.1-(-0.8*0.6-0.4*0.1)\\\Delta Cp=-0.4*0.6+0.4*0.1+0.8*0.6+0.4*0.1\\\Delta Cp=0.4*0.6+0.4*0.2\\\Delta Cp=0.32$

Now the Lift Coefficient is given as

$C_L=\Delta C_p cos(\alpha_i)\\C_L=0.32\times cos(4*\frac{\pi}{180})\\C_L=0.3192$

Now the coefficient of moment about the leading edge is given as

$C_M=-0.3*0.4*0.6-(0.6+\dfrac{0.4}{3})*0.2*0.4\\C_M=-0.1306$

So the lift coefficient is 0.3192 while that of the moment about the leading edge is-0.1306.

5 0

3 years ago

Using the Distortion-Energy failure theory: 8. (5 pts) Calculate the hydrostatic and distortional components of the stress 9. (1

WITCHER [35]

Answer:

Detailed solution is given below:

7 0

4 years ago

Environmental assessments (EAs) are an important component of any civil engineering project. Delgado Engineering has been contra

Tom [10]

Answer:

Environmental assessments (EAs) are an important component of any civil engineering project. Delgado Engineering has been contracted to design and assess a multibillion-dollar urban rail center in a city, which is divided in the middle by a river. The center will be built on a previously unused island in the center of the river. For each of the four types of civil engineers (construction engineer, geotechnical engineer, structural engineer, transportation engineer), explain why they should be involved in the project—or why they would not be relevant to the project—and what their role would be. Then describe how the EA would proceed, including what might be included in the environmental impact assessment process, such as the use of geographic information systems. Finally, explain what might be in the environmental impact statement or why you think there may be a finding of no significant impact.

6 0

3 years ago

A binary star system consists of two stars of masses m1m1m_1 and m2m2m_2. The stars, which gravitationally attract each other, r

d1i1m1o1n [39]

Answer:

$a_c_2=\dfrac{a_c_1\times m_1}{m_2}$