Definition of Compression Member

A compression member is a structural component that is subjected to an axial compressive force, also known as a column or strut. The function of a compression member is to resist buckling or bending under the action of an axial compressive force.

Effective Length

The effective length of a compression member is defined as the distance between the points of contraflexure or inflection, where the bending moment is zero, under the action of an axial compressive force. It is the distance at which the compression member is free to buckle or bend under the action of an axial compressive force.

Least Lateral Dimension

The least lateral dimension of a compression member is the minimum cross-sectional dimension perpendicular to the axis of the member. It is the dimension that is perpendicular to the direction of the axial compressive force.

Ratio of Effective Length to Least Lateral Dimension

The ratio of effective length to least lateral dimension is an important parameter that determines the stability of a compression member. It is denoted by the symbol KL/r, where KL is the effective length and r is the least lateral dimension.

If the ratio KL/r is less than or equal to 12, the compression member is considered to be short and is capable of resisting buckling or bending under the action of an axial compressive force.

If the ratio KL/r is greater than 12, the compression member is considered to be long and is susceptible to buckling or bending under the action of an axial compressive force.

Classification of Compression Members

Based on the ratio of effective length to least lateral dimension, compression members can be classified as follows:

- Short Compression Members: KL/r ≤ 12
- Intermediate Compression Members: 12 < kl/r="" ≤="" />
- Long Compression Members: KL/r > 120

Conclusion

In conclusion, a compression member is termed as a column or strut if the ratio of its effective length to the least lateral dimension is more than 3. This signifies that the compression member is long and is susceptible to buckling or bending under the action of an axial compressive force. Hence, it is important to consider the effective length and least lateral dimension of a compression member while designing a structure to ensure its stability and safety.