Glass Expert Performs a Window Defect Analysis

California glass expert was asked to analyze a window defect that appears as a streak in the window. The glass failure analysis showed that the streaks in the window were  strings of bubbles near the surface of the glass. Upper right is a photograph of the window defect which appears as streaks. Upper left is a macro-photograph of the near surface bubbles that cause the defect. This is a manufacturing defect.

Glass Expert Witness Services

Read Consulting is a California failure analysis laboratory that provides a complete line of glass expert witness services. These include glass failure analysis, window damage assessment,  patent expert witness support and stress testing. In addition Read Consulting also offers glass expert witness support in all areas of glass and ceramic machining and processing.  Process and device patent expertise is also provided.  

Failure Analysis Expert Examines a Broken Champagne Bottle

A California failure analysis expert witness was asked to perform a glass failure analysis on a champagne bottle that had failed "spotnaeously". Because champagne is under pressure and in glass, there are warnings not to use a cork screw to remove the cork. However, there are cases where the cork is stuck and people will use a tool to extract the cork. The danger is that the tool can damage the inner wall of the bottle neck and initiate a crack that will cause bottle failure. In the present case, a tool was used to pry the cork out and it caused "chatter" damage on the inner wall of the neck very near the top. This damage initiate a crack that finally caused bottle failure. Upper left is a 20X photomicrograph of the damage to the neck inner wall. Upper right is a 20X photomicrograph of the failure origin on the fracture surface. Again, because a champagne bottle is under pressure, one should never use a tool to remove a stubborn cork. There was no manufacturing defect; this bottle failed as a result of handling damage.

Glass Expert Performs a Bottle Failure Analysis

A California Glass failure analysis expert witness was asked to examine a failed wine bottle. A portion of the bottle top broke off midway down the cork as the cork was being removed. The root cause failure analysis revealed that the bottle had received a impact to the side. The distinct Wallner lines (see the photomicrograph above) located near the origin demonstrate that the impact was severe. The interaction of the crack front with the vibrations generated by the impact caused very visible Wallner lines. There was no manufacturing defect associated with this failure. When and how the impact occured cannot be determined from this failure analysis.