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This paper presents an experimental and analytical investigation of the effect of specimen geometry on the tensile properties and damage behavior of glass fiber reinforced polymer woven laminates at cryogenic temperatures. Cryogenic tensile tests were performed on three types of specimens, and acoustic emission monitoring was employed to characterize the damage development during loading. A two-dimensional finite element analysis was also carried out for three tensile test specimens in order to have a thorough understanding of the progressive failure behavior. A comparison was made between simulation and experiment.

To evaluate the tensile properties of SL-ES30 glass-cloth/epoxy laminates for superconducting magnets in fusion energy systems, tensile tests were examined both experimentally and analytically. The tensile tests were conducted in accordance with JIS K 7054 at room temperature and liquid nitrogen temperature (77 K). The general specimen geometry was a rectangular dog-bone shape with constant gage length but with each specimen size having a different specimen width. The experimental finding provides the data for analytical modeling. The model utilizes two damage variables that are determined from experimental data. A finite-element method coupled with damage was adopted for the extensional analysis. The effects of temperature, specimen geometry, and gripping method on the tensile properties are examined.

This paper discusses the fracture and the adiabatic heating of austenitic stainless steels that may be used in cryogenic structures for the superconducting magnets of magnetic fusion reactors. Elastic–plastic fracture toughness tests were performed on compact specimens in liquid helium at 4 K. Adiabatic heating was detected by measuring the internal temperature. The effect of test specimen size and side grooving on the cryogenic fracture toughness, and the temperature rise during dynamic crack growth are examined. A size independent toughness parameter results in the case of side-grooved specimens. The effect of inclusion content on the fracture mechanics parameters is also discussed.

Summary JJ1 type austenitic stainless steel is emerging as the preferred structural material for nuclear fusion reactor superconducting magnet casings designed to operate at the temperature of liquid helium (4 K). To evaluate the cryogenic fracture toughness and temperature rise of tungsten inert gas (TIG) welds in 200 mm thick forged JJ1 type austenitic stainless steel plate for the next generation of nuclear fusion reactor superconducting magnets, clastic-plastic fracture toughness (J1C) tests were conducted with 1T compact tension specimens at 4 K. The tests were conducted to ASTM E813–87 standard specifications for determination of J1C by the unloading compliance technique to monitor crack growth. Au/0.07%Fe-chromel thermocouples were used to measure the temperature rise near the crack tip. The effects of the specimen sampling position and nitrogen content on J1C are examined. Specimens were examined by scanning electron microscopy (SEM) after fracture testing. The effect of the inclusion content on t...