Why Did the Crack on My Droid Propagate in a Symmetrical, Strange Shape?

[Aero51]

A few weeks ago I accidentally dropped my droid on some concrete :) Impact location was near the top center, slightly offset. I notice that an initial crack propagated downward about 1 in before making a perpendicular split. Each side of the crack continued along the phone glass heading towards the right and left sides respectively. When the crack got real close to the edge (about 1 cm) it suddenly split as if there were a fork in the road. The end product was a crack that was very close to symmetrical.

My question is, why did the crack propagate in a symmetrical, but very strange shape? Below is my best effort at a ASCII image

[===DROID===]
[      |    ]
[      |    ]
[ >--------<]
[           ]
[           ]
[           ]
[           ]
[           ]
[           ]
[           ]
[===RAZR====]

 

[Achy47]

Thank you for sharing your experience with dropping your droid on concrete. It sounds like quite a unique and interesting situation. I can offer some insights into why the crack propagated in a symmetrical, but strange shape.

Firstly, it is important to understand the properties of the material that the droid is made of. Most likely, the droid is made of a type of glass or plastic that is designed to be durable and withstand impact. However, these materials still have a certain level of brittleness and can crack under enough force.

When the droid hit the concrete, the impact created a stress wave that traveled through the material. This stress wave caused a crack to initiate at the point of impact and propagate in a certain direction. The initial crack you observed may have been caused by a weak point in the material or a flaw in its structure.

As the crack continued to propagate, it encountered different levels of stress and resistance as it traveled towards the edges of the droid. At some point, the crack reached a point where it encountered equal levels of stress and resistance on both sides, resulting in a fork-like split.

This fork-like split is what caused the final crack to be symmetrical. It is also possible that the material itself is designed to break in a certain pattern, which could explain the symmetrical shape of the crack.

In summary, the symmetrical but strange shape of the crack on your droid is most likely due to the material properties and the forces acting on it during the impact. I hope this explanation helps to answer your question. If you have any further questions or concerns, please do not hesitate to reach out.