Which stress category arises from cyclic application of a stress, including thermal cycling?

Which stress category arises from cyclic application of a stress, including thermal cycling?

• A. Thermal stress
• B. Structural stress
• C. Pressure stress
• D. Fatigue stress

Answer: (D)

Cyclic loading causes damage to materials through repeated stress reversals. With many cycles, tiny cracks tend to initiate at flaws or stress concentrators and then grow with each cycle until failure occurs. Thermal cycling, where temperatures rise and fall repeatedly, induces cyclic strains even if the external load is not changing, so it a common driver of fatigue. This ongoing, cycle-by-cycle damage accumulation is what defines fatigue stress. In contrast, thermal stress comes from temperature differences that create stresses without necessarily involving repeated loading, structural stress arises from static loads, and pressure stress from steady pressure. So fatigue best captures the idea of damage from repeatedly applied stresses, including those caused by thermal cycling.

Cyclic loading causes damage to materials through repeated stress reversals. With many cycles, tiny cracks tend to initiate at flaws or stress concentrators and then grow with each cycle until failure occurs. Thermal cycling, where temperatures rise and fall repeatedly, induces cyclic strains even if the external load is not changing, so it a common driver of fatigue. This ongoing, cycle-by-cycle damage accumulation is what defines fatigue stress. In contrast, thermal stress comes from temperature differences that create stresses without necessarily involving repeated loading, structural stress arises from static loads, and pressure stress from steady pressure. So fatigue best captures the idea of damage from repeatedly applied stresses, including those caused by thermal cycling.