science

Korsunsky Work-of-Indentation Approach

Korsunsky Work-of-Indentation Approach is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Korsunsky Work-of-Indentation Approach rather than just read about it. In short: The Korsunsky work-of-indentation approach is a method of extracting values of hardness and stiffness for a small volume of material from indentation test data, first developed by Alexander M. Korsunsky.

Key takeaways

Korsunsky Work-of-Indentation Approach belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Korsunsky Work-of-Indentation Approach to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Korsunsky Work-of-Indentation Approach from memory before moving on to harder problems.

Reference excerpt

The Korsunsky work-of-indentation approach is a method of extracting values of hardness and stiffness for a small volume of material from indentation test data, first developed by Alexander M. Korsunsky. Instead of relying on measurements or assumptions pertaining to the observed area of contact between indenter and sample, the method uses the load-displacement data registered in the Continuously Recorded Indentation Testing (CRIT) that is widely applied in nanoindentation experiments. In particular, the Korsunsky method re-defines hardness and expresses it in terms of the energy (work) associated with indenting the surface of a material by the probe. The work-of-indentation used in the analysis may refer to the total, elastic or dissipated energy, depending on the formulation. The approach can be used in the analysis of thin coatings, nano-multi-layers, nanoscale features. The original application of the approach was developed for the problem of finding the composite hardness of a coated system. The composite hardness is known to vary depending on the applied load and or indentation depth. In the Korsunsky work-of-indentation approach, the composite hardness is given by a simple expression (the “knee function”) of the relative indentation depth (the indentation depth normalized with respect to the coating thickness), and the substrate and coating hardness. The function contains a single fitting parameter, which describes a wide range of composite and indenter properties such as coating brittleness, interfacial strength, indenter geometry, etc. This model of hardness determination has been verified by numerous researchers investigating different coated systems. This approach has undergone numerous modifications since its inception. Most recently, Jha et al. found that the Korsunsky work-of-indentation approach measures the nominal hardness of a material which is defined as the maximum load divided by the area of maximum contact. The nominal hardness of a material is different than its true hardness (determined by the Oliver-Pharr method), but the two concepts are interrelated. Jha et al derived an expression that determines the true hardness of a material from its nominal counterpart. In doing so, they employed a dimensionless energy-based parameter that relates the contact depth to the maximum depth of penetration. For a soft material, the difference between the contact depth and the maximum depth of penetration is small, and hence its nominal and true hardness values are practically the same. For a harder material these two types of hardness are different as the difference between them is large. The model proposed by Jha et al in its current form is applicable when the indenter is ideally sharp or when the maximum depth of penetration is sufficiently large compared to the indenter tip radius. The advantage of the modified work-of-indentation is that it does not require the computation of contact area, which is the main limitation of the conventional Oliver-Pharr method. The approach requires further modification in order to incorporate effect of bluntness at the tip of an indenter on the measured hardness of a material.

References

Worked examples

Example 1 — a first encounter with Korsunsky Work-of-Indentation Approach

Start with the simplest possible case. Write down what Korsunsky Work-of-Indentation Approach claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Korsunsky Work-of-Indentation Approach before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Korsunsky Work-of-Indentation Approach ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Korsunsky Work-of-Indentation Approach

In research: Korsunsky Work-of-Indentation Approach appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Korsunsky Work-of-Indentation Approach in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Korsunsky Work-of-Indentation Approach is common in secondary-school and first-year university syllabi. It links to neighbouring topics Hardness tests, so understanding it makes those chapters shorter.
In everyday life: Look for Korsunsky Work-of-Indentation Approach outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Korsunsky Work-of-Indentation Approach in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Korsunsky Work-of-Indentation Approach means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Korsunsky Work-of-Indentation Approach out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Korsunsky Work-of-Indentation Approach in simple terms?

Why does Korsunsky Work-of-Indentation Approach matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Korsunsky Work-of-Indentation Approach?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Korsunsky Work-of-Indentation Approach.