Error

There was an error loading the page.

Contributors

Vladimir Vingoradov

Feedback

From users who are members of CEG3302 :

Vladimir Vingoradov

said

Ready to use

4 years, 4 months ago

History

○

Vladimir Vingoradov 4 years, 4 months ago

Gave some feedback: Ready to use

○

Vladimir Vingoradov 4 years, 4 months ago

Published this.

○

Vladimir Vingoradov 4 years, 5 months ago

Created this.

There is only one version of this question that you have access to.

Question statement

An engineer naively calculates (wrongly) the maximum shear stress due to torsion of a member having a rectangular cross-section $a\times b$ (where $b=\var{k[j]}a$ ) by using the expression $\tau =TR/J$ (where $J$ is the polar moment of area of the section and $R$ is the largest distance from the centre of twist) and assumes that $GJ$ represents the torsional rigidity.

Give any introductory information the student needs.

			Name	Type	Generated Value

k	list	List of 8 items
beta	list	List of 8 items
j	integer	4
tau_a	number	0.828
tau_b	number	1.550
gamma	list	List of 8 items
error	integer	47

Automatically regenerate variables?

Name

Data type

Value

xxxxxxxxxx
 
[1.0,1.2,1.5,2.0,2.5,3.0,4.0,5.0]

JME function reference

Description

Describe what this variable represents, and list any assumptions made about its value.

Can an exam override the value of this variable?

Generated value: `list`

[ 1.0, 1.2, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0 ]

→ Used by:

tau_a
tau_b

Statement
Advice

Parts

Gap-fill
1. Gap Number entry
  Add

Gap-fill

Ask the student a question, and give any hints about how they should answer this part.

Making use of the results given in the table of slide 7 (Lecture notes), determine the percentage error in the calculations.

error,%=Unnamed gap

Advice

Wrong:

$\tau_\text{incorrect}=\frac{TR}{J}=\frac{T(\var{k[j]/2}a)}{J}.$

$J=\iint_A r^2 dA=\iint_A (z^2+y^2)dz\,dy=\int_{-0.5a}^{0.5a}\int_{-\var{k[j]/2}a}^{\var{k[j]/2}a} (z^2+y^2)dz\,dy=\var{precround(k[j]*(1+k[j]^2)/12,3)} a^4,$

$\tau_\text{incorrect}=\frac{T(\var{k[j]/2}a)}{\var{precround(k[j]*(1+k[j]^2)/12,3)} a^4}=\var{tau_a}\frac{T}{a^3}.$

Correct:

$\tau_\text{correct}=\frac{T}{a^2 (\var{k[j]}a)\gamma}=\frac{T}{\var{k[j]}\times\var{gamma[j]}a^3}=\var{tau_b}\frac{T}{a^3}.$

Error:

$\left|\frac{\tau_\text{incorrect}}{\tau_\text{correct}}-1\right|\times 100\%=\left|\frac{\var{tau_a}}{\var{tau_b}}-1\right|\times 100\%\approx\var{error}\%$

Give a worked solution to the whole question.

Use this tab to check that this question works as expected.

There was an error which means the tests can't run:

Part	Test	Passed?
Gap-fill
Gap-fill		Hasn't run yet
Number entry
Number entry		Hasn't run yet

This question is used in the following exam:

Tutorial 5 - Torsion by Vladimir Vingoradov in CEG3302.

Loading...

Error

Error

Metadata

Taxonomy: mathcentre

Taxonomy: Kind of activity

Taxonomy: Context

Contributors

Feedback

History

Comment

Checkpoint description

Vladimir Vingoradov 4 years, 4 months ago

Vladimir Vingoradov 4 years, 4 months ago

Vladimir Vingoradov 4 years, 5 months ago

Error in variable testing condition

Error

Warning

Generated value: `list`

Parts

Gap-fill

Loading...

Error

Error

Metadata

Taxonomy: mathcentre

Taxonomy: Kind of activity

Taxonomy: Context

Contributors

Feedback

History

Comment

Checkpoint description

Vladimir Vingoradov 4 years, 4 months ago

Vladimir Vingoradov 4 years, 4 months ago

Vladimir Vingoradov 4 years, 5 months ago

Error in variable testing condition

Error

Warning

Generated value: list

Parts

Gap-fill

Generated value: `list`