Nonlinear structural analysis

Coursework – Assessment Brief

UBGMUA-15-M Nonlinear structural analysis

June, 2020

Preamble

All assessments on this module are individual work. The work you submit must be your own

work. Submitting work that is copied in part or whole from another student with or without

their permission is an assessment offence.

You must fully attribute/reference all sources of information used during the completion of

your submission, failure to do so constitutes plagiarism, which is an assessment offence.

If you are not familiar with the definitions of plagiarism and collusion, more information

can be found here: https://www.uwe.ac.uk/study/academic-information/

assessments/assessment-offences

Please ensure you are familiar with assessment procedures and policies, which can be found

here: https://www.uwe.ac.uk/study/academic-information/assessments

Structure of assessments

This module is assessed by two components, A and B, weighted as 70% and 30% of the final

mark. To pass the module you must achieve a final mark of at least 40%. Component A is

a two hour written exam and component B is a coursework portfolio (1000 words). This assessment

brief is for component B, covering learning outcomes 3: Use non-linear finite element

analysis to design complex structures taking into consideration health and safety issues during

design stage. According to the university expectation marks and feedback for this assessment

will be returned to students within 20 working days. It is estimated that this work will take

approximately 30 h of learning effort.

Online blackboard submission due on the 3rd August 2020.

Marks and feedback for the assessment will be returned until the 23rd August 2020.

Note that UWE’s regulation mentions that the resit will be uncapped for assessments under-

1

1. DESIGN OF GEOMETRICALLY NONLINEAR STRUCTURES AGAINST SNAP-THROUGH EFFECT

taken in academic year 2019/20.

1 Design of geometrically nonlinear structures against snapthrough

effect

Consider the two von Mises truss structures shown in Fig. 1, subjected to a vertical load P, with

trusses of axial stiffness k = 105 Nm􀀀1, initial angle 0 = 

6 , a = 4m and linear or helical spring

of stiffness kE. You are free to assume any Young’s modulus value/cross-section for the truss

bars (e.g. a circular hollow section), as long as the axial stiffness k remains unchanged. You are

P

0



k k

a a

kE

(a)

P

0



k k

a a

kE

(b)

Figure 1: von Mises structures with (a) linear and (b) helical elastic springs.

asked to design the stiffness of the linear or helical spring with the minimum value required

to avoid the structures from becoming unstable. The structure that you have to consider is

marked in Table 1 with a cross mark, and you can ignore the other.

Student Linear spring Helical spring

ALMUTAIRI, MUTEB X

CHIU, CHEUK YIN X

KANAGARAJU, KEERTHANAA X

LIN, SICHENG X

Table 1: Structure assignement per student

A report (1000 words) describing your analysis and findings will have to be submitted to Blackboard.

The report should contain the following:

• The equation of equilibrium of the Von Mises structure that you have been asked to

analyse, including its points of critical stability.

• Five analytic solutions of the structure’s equilibrium path for multiple values of the designed

spring, ranging from a solution with no spring to the optimal value;

• Discussion of the results and conclusions of your analysis.

Dr Andre Jesus 2 University of theWest of England

1. DESIGN OF GEOMETRICALLY NONLINEAR STRUCTURES AGAINST SNAP-THROUGH EFFECT

The table below acts as a reference for marking of the portfolio

Mark Description

> 75 An excellent report, describing succinctly and accurately the structure’s

nonlinear behaviour, its stability and the influence of the elastic spring to

mitigate its unstable branch.

65 to 74 A sound report with accurate results but with some lack of clarity due to

minor omissions or unnecessary elements that have been added.

55 to 64 A fair report, with some lack of clarity and mistakes or inaccuracies in the

results of the analysis or their interpretation.

40 to 54 Considerable mistakes and poor presentation at a particular element of the

report (formulations, results interpretation, graphics, etc.)

35 to 39 An unclear report that exhibits considerable mistakes overall and that

shows fundamental flaws of nonlinear analysis.

0 to 34 An uninformative and incoherent report. Major errors on fundamental concepts

of structural analysis and the graphical and written presentation of the

report has been overlooked.

Table 2: Reference for portfolio marking assessment.

Dr Andre Jesus 3 University of theWest of England