1 liners from the Strength of Materials in Civil Engineering
Important 1 liners from the strength of materials are as under,
Endurance Limit
The Endurance Limit is the stress threshold at which a substance has a high chance of not collapsing under reversal of stress... Or, Endurance Limit is the stress level at which a substance cracks under a significant number of stress reversals...
Ductility
The maximum amount of pressure that can be extracted from a material until it cracks.
Malleability
The ability of a material to be distorted or dispersed in a variety of ways. Compressive forces are mostly to blame when rolling, pushing, or hammering.
Creep
The substance undergoes more displacement with the progression of time when continuously loaded past the Elastic limit.
Fatigue
Degradation of a material caused by repetitive periods of stress or strain leads to gradual cracking and ultimately fracture.
Tenacity
The ability to withstand fracture when subjected to a tensile load.
Toughness
Up to collapse, the ability to consume mechanical energy.
Hardness
Resistance of scratching and abrasion.
Resilience
When it is deformed elastically, it can store energy and then restore it when it is unloaded.
Hooke's Law
Strain and stress are proportional (within proportional limit).
Thermal Stresses
- Thermal stresses are the stresses caused by temperature changes (rise/fall).
- The actual definition of the coefficient of thermal expansion is the amount of strain created per unit change in temperature.
- Coefficient of thermal expansion unit = per degree Celsius
- Thermal expansion coefficients of various products are
- Aluminium = 24 x 10^(-6)
- Copper = 17.5 x 10^(-6)
- Steel = 12 x 10^(-6)
- The greater the coefficient of thermal expansion, the more susceptible the material is to temperature change.
- There is no tension created when the bar is free to grow due to temperature changes (rise/fall).
- Prismatic bar with both ends rigidly backed
- Compressive pressures form on the bar as the temperature rises.
- Tensile stresses form on the bar as the temperature drops.
- Copper bar is in series with steel bar
- Compressive stresses form on both copper and steel bars as the temperature rises.
- Tensile stresses form on both copper and steel bars as temperature decreases.
- A copper plate is parallel to a steel plate, forming a composite.
- As the temperature rises, compressive stress forms on copper, and tensile stress forms on steel.
- Tensile stress formed on copper as the temperature dropped, and compressive stress developed on steel.
- The copper rod is wrapped in a steel tube, which is rigidly fixed at both ends.
- Compressive pressures form on both copper and steel as the temperature rises.
- Tensile stresses form on both copper and steel as the temperature drops.
Notes
- Stress, Strain, and Moment of Inertia are tensor quantities that are neither scalar nor vector...
- Stress is contingent, while a strain is self-contained...
- A section's shear force is the sum of all transverse forces to the right and left of the section.
- The resulting moment at the section due to all transverse forces to the left or right of the portion is known as the bending moment.
- On either side of a concentrated load, the shear force is different...
- For either side of the concentrated load, the bending moment stays constant.
- The Shear Force is proportional to the slope of the bending moment diagram.
- The Load Intensity is proportional to the slope of the Shear Force diagram.
- The Curvature is proportional to the second derivative of the Deflection.
- Point of Contraflexure - Point where BMD changes sign. (BMD=0 at this section)
- Point of Inflection - Point where the deflected shape changes Curvature. (BMD=0 at this section)
- The Bending Moment at the Section is Maximum Or Minimum if the Shear Force at a section of a beam under bending is equal to zero.
So, these are the most important 1 Liners from the Strength of Materials (S.O.M), subject of the Civil Engineering Field.
Thanks for the reading.
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