# 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.