Exploring Bullet Deformation and Stress Resistance

[tuoni]

I've been working on a ballistics model for quite some time now, and I am getting close to finishing some parts of it, however, I am having trouble with bullet deformation. I simply have not found sufficient reference material to be able to complete the model.

Is there a clear relationship between deformation and the strength of a target?

Imagine two identical solid rods propelled into two different targets at equal velocity. The deformation rate in the first target is 1/m/Pa. The second target has a strength and/or density twice that of the first target. Will the deformation rate be twice that of the first target, or will it increase by square? Or is there some other relationship?

Flesh has an average shear strength of 0.4 MPa, and structural steel 140 MPa. In flesh, a bullet has a deformation onset (how deep in does it begin to deform) of 7 cm, and a deformation rate of 1/m/MPa. At what point between these two materials, does the bullet go from penetrating and fragmenting inside the target, to shattering on impact?

That's pretty much the issue at hand, how stress affects deformation.

I know that bullet design and construction is an important part of its performance, but for simplicity, let's consider the solid rod scenario only.

 

[Valerie Park]

The relationship between deformation and strength of the target can be expressed as a function of the stress experienced by the target. The basic idea is that when the stress applied to the target reaches a certain threshold, the bullet will begin to deform. This threshold may depend on various factors, like the angle of incidence, the mass of the bullet and the type of material it was made of.The deformation rate then increases with the stress applied to the target, as the bullet progressively deforms more and more. However, as the bullet deforms it also loses energy, and eventually it will reach a point where any further deformation would require more energy than what is available. At this point, the deformation rate will plateau and the bullet will either shatter or penetrate the target. The exact nature of the relationship between deformation and strength of the target will likely be highly complex and depend on numerous factors, so it may be difficult to determine an exact equation. However, it may be possible to come up with a general approximation based on existing data. A good starting point would be to measure the deformation rates in various materials at different stresses and establish an empirical relationship between the two. With enough data points, it should be possible to approximate the relationship between deformation and strength of the target.

 

[charng]

I can understand your frustration with not being able to find enough reference material for your ballistics model. Deformation and stress resistance are complex concepts that are influenced by various factors, such as the properties of the bullet and the target material, the speed and angle of impact, and even environmental conditions. It is important to have a thorough understanding of these factors in order to accurately model bullet deformation.

To answer your first question, there is indeed a relationship between deformation and the strength of a target. Generally, a stronger and denser target will result in less deformation of the bullet. However, the exact relationship can vary depending on the specific materials and conditions involved. It is not a simple linear relationship, as you have suggested in your scenario with the two identical rods and two different targets.

In order to accurately predict the deformation rate in a target, one must also consider the deformation onset, which is the point at which the bullet begins to deform. This can vary depending on the properties of the bullet and the target material. In your example, the bullet has a deformation onset of 7 cm in flesh and a deformation rate of 1/m/MPa. This means that for every 1 MPa of stress, the bullet will deform by 1/m (for example, 1 mm for every 1 m of length). However, this relationship may change at different stress levels and in different materials.

In terms of the point at which a bullet goes from penetrating and fragmenting to shattering on impact, this can also vary depending on the materials and conditions involved. It is not solely determined by the stress and deformation, but also by other factors such as the shape and construction of the bullet, and the angle and speed of impact.

In conclusion, stress does play a crucial role in bullet deformation and resistance, but it is a complex relationship that requires a thorough understanding of various factors. it is important to continue researching and gathering reference material to accurately model and predict these phenomena.