Question:easy
Beach marks are observed in
Beach marks are observed in
Show Hint
If you see "beach marks" or "clamshell marks" in a question about material failure, the answer is almost certainly "fatigue". These marks trace the history of the crack growing under cyclic loading.
Updated On: Jul 2, 2026
- Impact failure
- Tensile failure
- Shear failure
- Fatigue failure
Show Solution
The Correct Option is D
Solution and Explanation
Step 1: Think about what fractography, reading a broken surface, can tell an engineer.
Different ways of failing leave visibly different fingerprints on the fracture surface, a tensile overload, a shear failure, and a fatigue failure all look distinct under the naked eye or a low power microscope.
Step 2: Understand how beach marks physically form.
Fatigue failures grow slowly, crack by crack, cycle by cycle, often over months or years of fluctuating load. Whenever the loading pauses or changes, for example the machine is switched off overnight, the crack front leaves behind a faint ring, and thousands of these rings build up into visible concentric arcs that radiate out from the point where the crack first started, resembling ripples on a beach.
Step 3: Rule out the alternatives.
Impact failures usually show cleavage facets or dimples, tensile failures in ductile metals give the familiar cup and cone shape, and shear failures show smeared, sliding surfaces, none of these produce the characteristic concentric ring pattern, which is uniquely tied to the slow, cyclic nature of fatigue.
\[ \boxed{\text{Fatigue failure}} \]
Different ways of failing leave visibly different fingerprints on the fracture surface, a tensile overload, a shear failure, and a fatigue failure all look distinct under the naked eye or a low power microscope.
Step 2: Understand how beach marks physically form.
Fatigue failures grow slowly, crack by crack, cycle by cycle, often over months or years of fluctuating load. Whenever the loading pauses or changes, for example the machine is switched off overnight, the crack front leaves behind a faint ring, and thousands of these rings build up into visible concentric arcs that radiate out from the point where the crack first started, resembling ripples on a beach.
Step 3: Rule out the alternatives.
Impact failures usually show cleavage facets or dimples, tensile failures in ductile metals give the familiar cup and cone shape, and shear failures show smeared, sliding surfaces, none of these produce the characteristic concentric ring pattern, which is uniquely tied to the slow, cyclic nature of fatigue.
\[ \boxed{\text{Fatigue failure}} \]
Was this answer helpful?
0
Top Questions on Mechanical Metallurgy
- Match the following:
- TS PGECET - 2026
- Metallurgical Engineering
- Mechanical Metallurgy
- The stress at which the stress-strain curve deviates from linearity is:
- TS PGECET - 2026
- Metallurgical Engineering
- Mechanical Metallurgy
- The basis on which the Von Mises criterion is preferred compared to maximum shear stress criterion theoretically is:
- TS PGECET - 2026
- Metallurgical Engineering
- Mechanical Metallurgy
- Consider the following Assertion (A): The shape and magnitude of the stress-strain curve of a metal depend on its composition, heat treatment, prior plastic deformation, strain rate, temperature and state of stress during testing. Reason (R): Tensile strength and yield strength are strength parameters, whereas percent elongation and reduction of area are measures of ductility.
- TS PGECET - 2026
- Metallurgical Engineering
- Mechanical Metallurgy
- Want to practice more? Try solving extra ecology questions todayView All Questions