I've just read the phys.org new item which summarizes the conclusions by SpaceX about the cause of the September 1st 2016 anomaly.
I'm citing quotes in the news item which come from a SpaceX announcement which is further quoting investigators, so I am not sure I'm getting the correct picture yet:
"Investigators concluded that super chilled LOX can pool in these buckles under the overwrap. When pressurized, oxygen pooled in this buckle can become trapped; in turn, breaking fibers or friction can ignite the oxygen in the overwrap, causing the COPV to fail."
"Investigators determined that the loading temperature of the helium was cold enough to create solid oxygen (SOX), which exacerbates the possibility of oxygen becoming trapped as well as the likelihood of friction ignition."
Question: Does the term "buckles" refer to existing static indentations of some kind in the as-fabricated aluminum liner, or to spaces that are formed by the aluminum liner actually buckling during the loading process?
Update: The 2018 Florida Today article After 2016 launch pad explosion, SpaceX updating Falcon 9 for astronauts suggests that it is the tank that was buckled (lower your volume to avoid advertisements):
Changes in helium loading operations prevented a repeat of the problem believed to have caused the explosion: buckles in helium tanks that trapped slushy liquid oxygen in gaps between the tanks and their composite wraps. Friction "or other mechanisms" ignited oxygen in the upper stage.
While Falcon launches resumed fairly quickly, a redesigned helium bottle has not yet completed testing nor won NASA’s approval for crew launches.
The next launch date has now been announced as January 8, 2017, just a few days away. Does the plan to avoid this happening in the immediate future consist primarily of ways to change the helium loading process to keep it from getting so cold that liquid oxygen in these trapped spaces simply can't freeze into solid oxygen (SOX), or are they also going to try to prevent these pocket of LOX from forming between the Aluminum liner and the carbon overwrap in the first place?
Aluminum in contact with pure oxygen, carbon in contact with pure oxygen, huge stresses, huge vibrations, only a bit of friction necessary to start a reaction... no physical barrier?
He built gradually to a crying jag, during which he claimed to be deeply touched by the idea of an inhabited planet with an atmosphere that was eager to combine violently with almost everything the inhabitants held dear. He was speaking of Earth and the element oxygen.
“When you think about it boys”, he said brokenly, “that’s what holds us together more than anything else, except maybe gravity. We few, we happy few, we band of brothers - joined in the serious business of keeping our food, shelter, clothing and loved ones from combining with oxygen.”
--Kurt Vonnegut, God Bless You, Mr. Rosewater (1965)