Glass Failure Analysis of Wine Bottle

A recent failure analysis performed on a wine bottle revealed a manufacturing defect. The initiating manufacturing defect is a piece of unmelted glass (see photo above). More information on this can be found on my website: http://www.readconsulting.com/ There is a recent white paper that discusses the failure analysisi in detail.

Weld Failure on Crane

While studying a weld failure on a tower crane section, it was discovered that the weep(drain) holes were plugged. As a result, there was standing water that froze and split the weld. The failure mode was ductile overload that started at a stress concentrator created by the weld meniscus The destructive force is created by the ice forming a plug and the growth of the ice into the remaining water. The ice has a larger volume than the water from which it is formed. The water is non-compressable; therefore, force is created. In addition, it increases as the ice grows. In this case the force generated was sufficient to rupture the weld along the leg. The failure was discovered during the daily inspection, and the crane was taken out of service to be repaired.

Evaluation of Hurricane Windows

Window Expert has been involved in a large case involving the failure of hurricane windows. These windows are made from two layers of glass with a thick layer (0.05") of a flexible polymer.
The lesson from this effort has been that the polymers selected for producing windows that meet Miami Dade County requirements must have the required properties. However, Miami Dade does not specifically require the amount of accelerated aging that will prove that a window will be reliable for ten to twenty years (polymer degradation). As an experienced manufacturing engineer, I reccomend that anyone developing a system of this type be aware of the extreme environmental stresses that must be endured by these windows. The important environmental stresses include high temperature, high humidity (this includes the potential for standing water) and exposure to ultra violet light. A series of accelerated life tests should be developed to evaluate the long term reliability of these windows. MIL Std 883 is a good starting point for developing these tests.