failure of the tie rod at the anchorage point failure may also result when the clamping mechanism provides low contact pressure or a low bond which would result in the tie rod separating e g pulling out from the end cap under pressure the use of wedge type retention mechanisms 40 avoids such problems associated with conventional clamping anchoring mechanisms e g threaded connection and avoids high pre stresses on the tie rods 34 as a result lightweight composite tie rods 34 can be adapted to carry axial stresses while the pressure retaining shell 12 only carries hoop stress in the case of an overwrapped shell the wind angle of the composite overwrap can be between about 75 and about 90 degrees for example as such the need for a metallic stress carrying liner is avoided although one may be added for seal considerations avoiding any metallic stress carrying liner avoids the fatigue limitations of conventional current accumulator art by eliminating metal components fatigue life is enhanced and the overall weight of the accumulator 10 is reduced although the invention has been shown and described with respect to a certain preferred embodiment or embodiments it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings in particular regard to the various functions performed by the above described elements components assemblies devices compositions etc the terms including a reference to a u201c means u201d used to describe such elements are intended to correspond unless otherwise indicated to any element which performs the specified.