Rubber Failure Analysis: Inner Tube Failure

 California failure analysis lab performs rubber failure analysis on a failed bicycle inner tube. The rider was braking while descending a long steep hill. Toward the bottom of the hill his inner tube failed, and he heard a loud pop. The wheel rim was too hot to touch. A failure analysis was performed and the failure originated at a point on the tube that would have been in contact with a spoke "nut". It is believed that the tube was heated to the highest temperature at this location, and it softened to the point of failure. In addition, the tire pressure was elevated due to the heating of the rim from the friction of the brake pads. Upper right is a 40X photo-micro graph of the failure origin.

Rubber Failure Analysis: Rubber Seal Failure Analysis

A California failure expert witness was asked to determine the root cause of a rubber gasket leak. 

The molded rubber gasket seal was integrated into a hydraulic lift operating at 650 psi. Over time it had developed a very small hole and approximately 60 gallons of hydraulic oil escaped through this small leak. Read Consulting Failure Analysis Lab was asked to perform a detailed failure analysis to determine the cause of the leak.  The subject rubber seal failed as a result of a rubber molding defect. During the molding operation there was a region where the flowing rubber failed to re-bond properly. Over time the high pressure (650 psi) hydraulic oil created a hole in the weakened rubber and this resulted into a rubber failure and a hydraulic leak. Upper left is a 30X  photo-micrograph of the pinhole leak. The leak "protrudes" outward showing that the failure was created as a result of the hydraulic pressure. 

Rubber Failure Analysis Demonstrates Rubber Fatigue

California rubber failure analysis expert performs a failure analysis on a rubber paddle. This piece failed as a result of fatigue. The fatigue failure initiated on the outer surface at a stress riser and progressed inwards. This is damonstrated by the photomicrographs above. Upper left is taken at 10X. Upper right is taken at 40X. The fracture surface has all the aspects of a classic fatigue failure.