Force, Mechanical Properties and Structural Materials Explained

Force and Mechanical Properties

Force is capable of producing an action or modifying the state of motion of a body, or of producing deformations. The unit of force is the newton.

Mechanical properties are the characteristics that determine the behavior of materials under the forces acting on them.

Main Material Properties

• Resistance: the capacity to withstand forces without deforming excessively or breaking.
• Tenacity: the property of some materials that allows them to withstand forces and impacts without breaking easily.
• Weakness: the tendency of a material to break under a small force, either over time or intentionally.
• Elasticity: the property that allows materials to recover their original shape and size after the force that deformed them is removed.
• Plasticity: the property that allows materials to undergo permanent deformation and take different shapes without breaking.
• Rigidity: materials that cannot bend easily.
• Flexibility: materials that can bend easily.
• Ductility: the property of some materials to deform permanently into a thin thread without breaking.
• Malleability: the property of some materials to deform permanently under compression into sheets.
• Hardness: the property that indicates the resistance of a material to being scratched or penetrated.

Stress and Types of Stress

Stress is the effect of applying a force to a body that depends on its dimensions, shape and the type of force acting on it. There are five main types of stress:

• Tension: opposing forces (pulling in opposite directions) act on a body and tend to stretch or elongate it, depending on the material, section and thickness.
• Compression: forces act on an object in the same direction but opposite sense, tending to crush or shorten it.
• Buckling: the deformation undergone by long, thin bodies subjected to compression.
• Bending: forces or loads that act on a piece perpendicular to its longitudinal axis and tend to curve it. It depends on the material, length, section, and the body's resistance to bending, as well as the thickness of the edge.
• Torsion: the effect of forces that twist a body.

Shear or cutting concentrates two opposing forces on the same part of an element. These forces are enough to overcome the resistance the material provides.

Structures

A structure is a set of elements joined together. Its basic function is to withstand external and internal forces, support its own weight and the loads applied to it, and maintain stability.

A frame is a set of resistant elements joined together that constitute the skeleton of several objects or constructions. Types include metallic structures, reinforced concrete, buildings and towers.

IPN is a standardized I-shaped steel profile, where the flange thickness is defined as a standard, with a height of 80 mm or more depending on the profile.