Thank youBaluncore said:I guess by “on-site energy”, you mean “internal energy”?
As stress increases, the strain increases, and energy is stored in the elastic material.
There is a yield point, where the stress is partially relieved by plastic deformation.
If the stress is then removed the elastic strain will be reduced, but there will be some energy remaining in plastic strain where adjacent grains in the material have undergone different plastic deformation.
“Work hardening” is associated with remaining internal energy.
https://en.wikipedia.org/wiki/Work_hardening
“Annealing” can relieve the remaining internal energy.
The internal energy that remains will depend on the state of the grains within the material.
What is that material and what do you know about the internal grain structure?
Yes this problem is related to the Quantum mechanic and is about 2D materials.Baluncore said:OK, so my mind reading skills are sadly lacking.
What sort of strain are you referring to here ?
Is this Quantum Theory, or strength of materials ?
If you actually specify the subject, you may get a better answer.
Thank you so much.crashcat said:If I understand what you are asking, the answer is yes. Strain will affect the energy of an individual atom in the lattice. There is no simple formula I know of, it has to be solved with DFT. The typical method is to model the lattice with matched boundary conditions, but your unit cell is actually several unit cells large. You allow the atomic positions to migrate to the lowest energy position. Then take your optimized lattice and model again with one atom popped out, without allowing atoms to migrate. The difference is the "site energy" you're looking for. When you do this kind of modeling, you'll see it converge to a value as you increase the number of unit cells, i.e. 3x3 then 4x4 then 5x5. It doesn't take much to get rid of edge effects.
Hi @crashcat , can you provide an example of this from the literature? Whenever I see strain treated via tight binding, I only ever see it entering in the hopping Hamiltonian, rather than the on-site Hamiltonian (example: https://arxiv.org/abs/1511.06254).crashcat said:If I understand what you are asking, the answer is yes. Strain will affect the energy of an individual atom in the lattice. There is no simple formula I know of, it has to be solved with DFT. The typical method is to model the lattice with matched boundary conditions, but your unit cell is actually several unit cells large. You allow the atomic positions to migrate to the lowest energy position. Then take your optimized lattice and model again with one atom popped out, without allowing atoms to migrate. The difference is the "site energy" you're looking for. When you do this kind of modeling, you'll see it converge to a value as you increase the number of unit cells, i.e. 3x3 then 4x4 then 5x5. It doesn't take much to get rid of edge effects.
Strain refers to the deformation or change in shape of a material due to external forces. In terms of on-site energy, strain can affect the stability and strength of structures, as well as the efficiency of energy transfer and storage systems. This is because strain alters the molecular and atomic structure of materials, which can impact their physical and chemical properties.
Yes, strain can be controlled or minimized through careful design and selection of materials, as well as proper maintenance and monitoring of structures and systems. This can help prevent excessive strain and potential failure of on-site energy systems, ensuring their long-term efficiency and reliability.
Some common sources of strain in on-site energy systems include external forces such as wind, seismic activity, and thermal expansion/contraction. Internal factors such as material properties, design flaws, and aging can also contribute to strain in these systems.
Excessive strain can significantly reduce the lifespan of on-site energy systems. It can cause structural damage, fatigue, and wear, leading to potential failures and the need for costly repairs or replacements. Therefore, it is crucial to consider strain in the design and maintenance of these systems to ensure their longevity.
While excessive strain can be detrimental to on-site energy systems, controlled and intentional strain can also have benefits. For example, piezoelectric materials can convert mechanical strain into electrical energy, which can be used to power sensors or other devices. Additionally, strain can be used to optimize the performance of certain materials, such as in the case of shape memory alloys.