| 摘要 |
<p>A rig for testing creep fatigue comprises first and second elongate members 101, 102. First member 101 is coupled at a lower end to base 107. A third member 103 couples an upper end of first member 101 to a lower end of second member 102. The members expand or contract in response to temperature changes. Third member 103 comprises a material which expands or contracts at a different rate to that of the other members, such that total movement of the upper end d of second member 102 is defined by an aggregate or cumulative expansion or contraction of the first, second and third members. Movement of upper end d can therefore be made greater or less than the movement of a single equivalent member by using a third member 103 having a thermal expansion which is lower or higher than the other members. In use, a test piece (not shown) having a weld is fixed between the upper ends of second member 102 and support 106, so that temperature dependent movement of second member 102 imparts stress to the test piece. A plurality of second and third members may form a linear array (see fig 5).</p> |
