Engineering HSC Syllabus Summary

Resource Description

Engineering HSC Syllabus Summary

 

Civil Structures 

 

Engineering mechanics and hydraulics

• Stress and Strain

• Strain 

• The proportional change in length caused when a specimen is under load 

• Strain = e(extension m)L(original length m)

• No units (ratio)

• Shear stress

• A measure of the internal reaction that occurs in response to an externally applied load

• Stress σ Pa= P (Load N)A(Area m2)

• Engineering and working stress

• Engineering stress – the original C.S.A is used to calculate the stress for every value of the applied force

• Working stress – The actual or constantly changing C.S.A value is used to calculate the stress 

• Yield stress, proof stress, toughness, Young’s Modulus, Hooke’s law, engineering applications

• Yield stress– the stress where there is a marked increase in strain without an increase in stress. Yield stress is always greater than the elastic limit, but less that the UTS
• Proof stress– used as a measure on materials that do not show a marked yield point. Usually a set amount of strain is given to the material, usually 15 or 2% and the amount of stress can be calculated
• Toughness– indicated by the area under the curve in a stress/strain diagram. Ability of a material to absorb energy
• Young’s Modulus– Measure of the stiffness of a material. Applies up to the elastic limit of a material. The gradient of the straight line in section of the graph indicates YM.

Hooke’s law– the amount of elastic deformation that a material can sustain in tension or compression before it undergoes permanent plastic deformation.