Abstract:
PROBLEM TO BE SOLVED: To provide a stress sensor capable of precisely measuring stress fluctuation changed after setting in comparison with stress usually applied to a structure. SOLUTION: The stress sensor includes a cylindrical body 4 having an outer circumference part tightly fitted to a circular hole 3, which is formed in a part requiring measurement of internal stress in a structural material such as a shroud 1 to be measured and provided with an axial line crossing a force line of stress to be measured at right angles, a gage fixing plate 25, which is arranged in an internal hole 3 of the cylindrical body 4 with a gage fixing face crossed across the axial line of the cylindrical body 4 at right angles, and a plurality of distortion gages r1-r4 arranged on the gage fixing plate 25 while their distortion detection directions are matched with radiation directions with respect to the axial line of the circular hole for detecting circular distortion of the circular hole 3. COPYRIGHT: (C)2007,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To realize a low cost and therewith obtain a signal which resists the error of the introduction position of a water pressure and the interference of installation water depth and accurately corresponds to an effective earth pressure. SOLUTION: Filters 34, 35 are placed in an air gap 10 sandwiched by 2 pieces of rigid plates 13, 14 forced by the earth pressure, and therefore the water pressure is forced but a sand pressure is not forced. Accordingly, a load cell 41 having structure without the sensitivity to the water pressure detects only the effective earth pressure. A signal cable 51 can be passed through in the air gap 10 and then a plurality of pressure transducers 1, 2 can be effectively connected and also the signal cables 51, 52 can be inserted through the inside. Consequently, the distribution pressure in a depth direction can be accurately measured. In the point part, an insertion head 71 to make insertion into the earth easy is attached to a support body 23. A plurality of the pressure transducers 1, 2 are connected one after the other via a coupling support body 24, and also the coupling is made rigid by bridging a coupling plate 61.