New type of Nb3Sn fiber-reinforced superconductors for high-field pulsed magnet and effect of thermal stress

1994 ◽  
Vol 114 (3) ◽  
pp. 1-14 ◽  
Author(s):  
Kazuaki Arai ◽  
Hiroshi Tateishi ◽  
Masaichi Umeda ◽  
Ko Agatsuma
Keyword(s):  
Thermal Stress ◽  
High Field ◽  
Fiber Reinforced ◽  
Pulsed Magnet ◽  
New Type

scholarly journals The research on precise forming technology of “λ” type composite skin

2021 ◽  
Vol 30 ◽  
pp. 263498332199474
Author(s):  
Qiang Guo ◽  
Kai He ◽  
Hengyuan Xu ◽  
Youyi Wen
Keyword(s):  
Carbon Fiber ◽  
Middle Layer ◽  
Fiber Reinforced ◽  
Process Verification ◽  
Forming Technology ◽  
Fiber Reinforced Materials ◽  
New Type ◽  
Carbon Fiber Reinforced ◽  
Type Composite ◽  
Reinforced Materials

With the application of “ λ” type composite skin becoming more and more extensive and diversified, its precise forming technology is also widely concerned. This article mainly solves the quality problems of “ λ” type corner area, such as delamination dispersion and surface wrinkle, which exist in reality commonly in the manufacturing process. The prepreg is heated along the corner area of the tooling to solve the problem that prepreg is difficult to be compacted due to the large modulus of carbon fiber in “ λ” type corner area. Furthermore, two precompaction tests are creatively increased at 16 layers (middle layer) and 32 layers (last layer) for the thick structure, respectively, to ensure the compaction effect of the blank. In addition, combined with the characteristics of highly elastic rubber and carbon fiber-reinforced materials, a new type of soft mold structure with proper flexibility and good stiffness is proposed innovatively through the reasonable placement of carbon fiber-reinforced materials and the setting of exhaust holes according to the structure characteristics of “ λ” type root skin. Through further process verification, it is shown that the improved process has effectively solved the problems of wrinkles and internal delamination at the sharp corners of parts and realized zero-defect manufacturing of “ λ” type root skin for the first time.

On multistage development of ITER High Field Side Reflectometry diagnostic module design based on thermal stress numerical assessment

2019 ◽  
Vol 146 ◽  
pp. 1237-1241
Author(s):  
D. Mamchits ◽  
A. Novokshenov ◽  
A. Nemov ◽  
A. Borovkov ◽  
V. Lukyanov ◽  
...  
Keyword(s):  
Thermal Stress ◽  
High Field ◽  
Module Design ◽  
Numerical Assessment ◽  
Diagnostic Module

Science and Techniques Using Pulsed Magnetic Fields

MRS Bulletin ◽  
1993 ◽  
Vol 18 (8) ◽  
pp. 44-49 ◽  
Author(s):  
J.J.M. Franse ◽  
N. Miura
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
High Field ◽  
Materials Science ◽  
Copper Wire ◽  
Field Research ◽  
Outer Diameter ◽  
Electricity Grid ◽  
Pulsed Magnet ◽  
Time Profiles

In this article, we examine materials behavior in the magnetic field region from about 40 T to 500 T using pulsed magnet technology. Examples of materials science using two different pulsed magnet technologies are described in this article.Semicontinuous MagnetsSince the late 1960s, the University of Amsterdam has operated a semicontinuous magnetic field installation that produces magnetic fields up to 40 T with typical time constants of about one second. The magnet coil is constructed from hard-drawn copper wire with a reinforcement cylinder of maraging steel positioned at roughly one third of the outer diameter. Before operation, the coil is cooled to 30 K by cold neon gas. The power for this installation is taken directly from a 10 kV connection to the public electricity grid. By means of a thyristor-based power control system, highly flexible field-time profiles can be realized: step-wise pulses can be generated with field levels constant within 10−4 during 100 ms; linearly increasing and decreasing fields as well as exponentially ripple-free decreasing fields are other examples of standard field-time profiles. Among the measuring techniques frequently used are magnetization, magneto-transport, quantum oscillations, relaxation phenomena, etc. Temperatures at which experiments can be performed range from 400 mK to room temperature. In the Netherlands, the Amsterdam High Field Facility has recently been combined with the High Magnetic Field Laboratory in Nijmegen, where static magnetic fields up to 30 T are produced in hybrid magnet systems, to form the Amsterdam-Nijmegen Magnet Laboratory (ANML). The high field research of ANML comprises semiconductors, magnetism in transition-metal compounds, heavy-fermion physics, superconductors, organic conductors, and magnetic separation. We present here a few selected topics.

Multi-pass laser cutting of carbon/Kevlar hybrid composite: Prediction of thermal stress, heat-affected zone, and kerf width by thermo-mechanical modeling

2020 ◽  
Vol 234 (9) ◽  
pp. 1228-1241
Author(s):  
K Moghadasi ◽  
KF Tamrin
Keyword(s):  
Thermal Stress ◽  
Heat Affected Zone ◽  
Laser Cutting ◽  
Manufacturing Industry ◽  
Element Model ◽  
Kerf Width ◽  
Scanning Electron Micrographs ◽  
Fiber Reinforced ◽  
Heat Accumulation ◽  
Damage Initiation

Numerical modeling offers considerable promise to reduce costs associated with trial-and-error process in the manufacturing industry. In laser cutting of fiber-reinforced composites, the developed thermal stress in the cut region has considerable influence on the application of the machined composite and the end product quality. Nevertheless, measurement of the thermal stress is quite challenging in practice. Here, an uncoupled thermo-mechanical finite element model is developed to accurately predict formation of heat-affected zone, kerf width, thermal field, and thermal residual stress of an anisotropic carbon/Kevlar fiber reinforced composite during multi-pass laser cutting process. A novel approach of element deletion incorporating temperature-dependent Hashin failure criteria and VUMAT subroutine is proposed. The study is carried out using Abaqus interlinked with Fortran compiler to define laser Gaussian beam (DFLUX subroutine) and material removal (VUMAT subroutine) for determining the temperature gradient and cut characteristics, respectively. The numerical results agree well with the experimental scanning electron micrographs of heat-affected zone and kerf width. In addition, residual temperature after subsequent pass results in greater temperature distribution and heat accumulation. It has also been established that the strength of composite gradually decays with the increase of temperature due to stiffness (elastic moduli) degradation in the area of the cutting zone, accelerating damage initiation in both fibers and matrix.

Sign in / Sign up

Export Citation Format

Share Document