Which parameter MOST affects the stress variation in a composite beam?

The parameter that most significantly affects the stress variation in a composite beam is the modulus of elasticity, denoted as E. This is because the modulus of elasticity is a measure of a material's ability to deform elastically (i.e., non-permanently) when subjected to stress. In composite beams, where different materials are bonded together, the disparity in the modulus of elasticity between the materials will lead to differences in the strain experienced by each material under load.

As the loads are applied, each material will respond according to its modulus of elasticity, affecting how stress is distributed along the beam. Higher modulus materials will experience lower strains and thus affect how the overall beam carries loads. Understanding the varying moduli of the materials helps engineers predict how stress will vary across the composite beam, which is crucial for ensuring structural integrity and performance under different loading conditions.

Other parameters—such as distance to the neutral axis, yield stress, and the width of the section—play a role in the overall strength and behavior of the beam but do not directly influence the fundamental stress distribution in the same way that the modulus of elasticity does. The distance to the neutral axis affects the moment of inertia calculation, yield stress relates to overall strength, and width influences the beam's overall capacity