Strength of materials definition: The ratio of the largest (maximum) load carried in a tensile test to the original cross-sectional area of the test piece is called what?

Introduction / Context:
Tensile testing provides a stress–strain curve and key strength parameters. The identification of elastic limit, yield stress, ultimate stress, and breaking (fracture) stress is fundamental to material selection and design safety factors.

Given Data / Assumptions:

• The 'largest load' refers to the maximum force the specimen sustains during the test before necking reduces the load capacity.
• Stress referenced to the original cross-sectional area (engineering or nominal stress).
• Standard tensile test conditions.

Concept / Approach:
Engineering stress is defined as load / original area. The highest value of this engineering stress during the test is the ultimate tensile stress (UTS). Yield stress is the stress at which plastic flow begins (e.g., 0.2% offset). Breaking stress refers to stress at fracture load on the original area, which is typically less than the UTS for ductile materials.

Step-by-Step Solution:

Verification / Alternative check:
Compare with the stress at fracture: P_fracture / A0, which can be less than UTS because the load typically drops after necking in ductile materials.

Why Other Options Are Wrong:

• Elastic limit / yield stress occur at lower loads before the maximum.
• Breaking stress is at fracture load, not the maximum load necessarily.
• True stress at maximum load uses instantaneous area; the question specifies original area → engineering UTS.

Common Pitfalls:
Confusing yield strength with UTS; mixing true stress (uses current area) with engineering stress (uses original area).

Final Answer:
ultimate stress