ISO 7685:2019 pdf free
ISO 7685:2019 pdf free.Glass-reinforced thermosetting plastics (GRP) pipes一Determination of initial ring stiffness
Loading machine, comprising a system capable of applying, without shock, a compressive force (suitable for Method A or B) at a controlled rate through two parallel load application surfaces conforming to 5.2 so that a horizontally orientated pipe test piece conforming to Clause 5 can be compressed vertically.The accuracy of loading shall be ±1 % of the maximum indicated load.
The surfaces shall be provided by a pair of plates (see 5.2.2), or a pair of beam bars (see 5.2.3), or a combination of one such plate and one such bar, with their major axes perpendicular to and centred on the direction of application of the load F by the compressive-loading machine, as shown in Figure 1. The surfaces in contact with the test piece shall be flat, smooth, clean and parallel.
Plates and beam bars shall have a length at least equal to that of the test piece (see Clause 6) and a thickness such that visible deformation does not occur during the test.
Parallelism between the plates, beams, or plate and beams, at the centreline and along direction of axis of pipe is recommended to be within a gradient of 1 mm/m or 1:1 000. The parallelism is more critical for higher stiffness pipes. The parallelism should be verified at minimum pipe opening and at maximum pipe opening for the machine.
Each test piece shall be a complete ring cut from the pipe to be tested. The length of the test piece shall be as specified in the referring standard, with permissible deviations of ±5 %. Where a referring standard does not exist, or does not specify the length of the test piece, the length shall be 300 mm±15 mm.The cut ends shall be smooth and perpendicular to the axis of the pipe.
Straight lines, to serve as reference lines, shall be drawn on the inside or the outside along the length of the test piece at 60° intervals around its circumference.ISO 7685 pdf free download.
