Relaxation of Internal Forces in a Wound Reel of Magnetic Tape

1965 ◽  
Vol 32 (4) ◽  
pp. 865-873 ◽  
Author(s):  
H. Tramposch

Equations were developed to predict the relaxation of the internal stresses of a wound reel of magnetic tape, assuming a homogeneous and isotropic material which, under shear, exhibits instantaneous elasticity, delayed elasticity, and creep; and under hydrostatic stressing, shows elastic behavior. Numerical examples obtained with the aid of a high-speed digital computer indicated that the internal stresses introduced during the winding operation continue to relax. Given sufficient time in storage, the wound reel will approach stress-free conditions, thus exposing the tape to mechanical damage during transportation and reuse.

1967 ◽  
Vol 34 (4) ◽  
pp. 888-894 ◽  
Author(s):  
H. Tramposch

Equations were developed to describe the relaxation of the internal stresses of a wound reel of magnetic tape, with allowances for the effects of surface roughness between tape layers and unequal thermal expansion of hub and tape-layer body. Numerical examples obtained with the aid of a high-speed digital computer indicated that the surface roughness as well as the unequal thermal expansion of hub and tape-layer body greatly affect the internal stress distribution. Essentially independent of the surface roughness, a typical reel, when stored at 120 F after being wound at 70 F and when the coefficient of thermal expansion of the hub is three times the value of the tape material, will approach stress-free conditions about 80 percent earlier than when it is stored at the winding temperature.


2020 ◽  
Vol 10 (15) ◽  
pp. 5182
Author(s):  
Daoping Liu ◽  
Dingli Zhang ◽  
Qian Fang ◽  
Zhenyu Sun ◽  
Jiwei Luo ◽  
...  

A super-span tunnel that has the characteristics of a large excavation area, a small high-span ratio and a significant spatial effect exhibits a complex mechanical response during the excavation process. In this paper, taking the Badaling Great Wall station in Beijing, China as the engineering background, a case study of field monitoring a super-span tunnel has been presented. A typical monitoring section was selected in the super-span transition section of the tunnel and the deformation and forces of both the surrounding rock and the support structures were systematically monitored. The dynamic evolution and the spatial distribution characteristics of the monitoring data, including the internal displacement of the surrounding rock, the tunnel displacement, the contact pressure between the surrounding rock and the primary supports, the contact pressure between the primary and secondary supports, the axial forces in the bolts and cables, the internal forces in both the steel arches and the secondary supports and the internal stresses of the surrounding rock, were analyzed. The results of the monitoring and the analyses have shown that the deformation and the forces acting on both the surrounding rock and the tunnel’s lining are directly related to the construction procedures, the geological conditions and the locations in the super-span tunnel. According to the results, a few suggestions to improve the construction of the tunnel have been proposed.


Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1664
Author(s):  
Do Hoon Cho ◽  
Seong Min Seo ◽  
Jang Baeg Kim ◽  
Sri Harini Rajendran ◽  
Jae Pil Jung

With the continuous miniaturization of electronic devices and the upcoming new technologies such as Artificial Intelligence (AI), Internet of Things (IoT), fifth-generation cellular networks (5G), etc., the electronics industry is achieving high-speed, high-performance, and high-density electronic packaging. Three-dimensional (3D) Si-chip stacking using through-Si-via (TSV) and solder bumping processes are the key interconnection technologies that satisfy the former requirements and receive the most attention from the electronic industries. This review mainly includes two directions to get a precise understanding, such as the TSV filling and solder bumping, and explores their reliability aspects. TSV filling addresses the DRIE (deep reactive ion etching) process, including the coating of functional layers on the TSV wall such as an insulating layer, adhesion layer, and seed layer, and TSV filling with molten solder. Solder bumping processes such as electroplating, solder ball bumping, paste printing, and solder injection on a Cu pillar are discussed. In the reliability part for TSV and solder bumping, the fabrication defects, internal stresses, intermetallic compounds, and shear strength are reviewed. These studies aimed to achieve a robust 3D integration technology effectively for future high-density electronics packaging.


2011 ◽  
Vol 46 (2) ◽  
pp. 121-142 ◽  
Author(s):  
M Nematzadeh ◽  
M Eskandari-Ghadi ◽  
B Navayi Neya

Using a complete set of displacement potential functions, the exact solution of three-dimensional elasticity equations of a simply supported rectangular plates with constant thickness consisting of a transversely isotropic linearly elastic material subjected to an arbitrary static load is presented. The governing partial differential equations for the potential functions are solved through the use of the Fourier method, which results in exponential and trigonometric expression along the plate thickness and the other two lengths respectively. The displacements, stresses, and internal forces are determined through the potential functions at any point of the body. To prove the validity of this approach, the analytical solutions developed in this paper are degenerated for the simpler case of plates containing isotropic material and compared with the existing solution. In addition, the numerical results obtained from this study are compared with those reported in other researches for the isotropic material, where excellent agreement is achieved for both thin and thick plates. The results show that increasing the thickness ratios of the plate causes compressive axial forces and central shear forces inside the plate. Finally, the internal forces and displacement components are calculated numerically for several kinds of transversely isotropic materials with different anisotropies and are compared with a finite element (FE) solution obtained from the ANSYS software, where the high accuracy of the present method is demonstrated. The effects of the material anisotropy are clearly revealed in the numerical results presented.


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