Theoretical and experimental studies of stress state of hollow cylinders with annular grooves

1984 ◽  
Vol 20 (4) ◽  
pp. 313-317
Author(s):  
Yu. N. Nemish ◽  
Yu. I. Vologzhaninov ◽  
A. I. Zirka ◽  
N. M. Bloshko ◽  
D. I. Chernopiskii
Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2087 ◽  
Author(s):  
Danhui Dan ◽  
Pengfei Jia ◽  
Guoqiang Li ◽  
Po Niu

It is typically difficult for engineers to detect the tension force of prestressed tendons in concrete structures. In this study, a smart bar is fabricated by embedding a Fiber Bragg Grating (FBG) in conjunction with its communication fiber into a composite bar surrounded by carbon fibers. Subsequently, a smart composite cable is twisted by using six outer steel wires and the smart bar. Given the embedded FBG, the proposed composite cable simultaneously provides two functions, namely withstanding tension force and self-sensing the stress state. It can be potentially used as an alternative to a prestressing reinforcement tendon for prestressed concrete (PC), and thereby provide a solution to detecting the stress state of the prestressing reinforcement tendons during construction and operation. In the study, both the mechanical properties and sensing performance of the proposed composite cable are investigated by experimental studies under different force standing conditions. These conditions are similar to those of ordinary prestressed tendons of a real PC components in service or in a construction stage. The results indicate that the proposed smart composite cable under the action of ultra-high pretension stress exhibits reliable mechanical performance and sensing performance, and can be used as a prestressed tendon in prestressed concrete structures.


Author(s):  
William Keith Rule

Recently experimental studies have been conducted using a novel form of the Taylor impact test consisting of sleeved cylinders. A soft material of known properties (OFHC Cu) was used for the core and the tight fitting sleeve was fabricated from the material of interest (AF1410 steel). On impact the mushrooming and sliding core places the sleeve in a stress state not normally found in Taylor impact testing. This paper describes a study conducted to evaluate the feasibility of backing out Johnson-Cook strength model coefficients from measured (post-test) deformed geometries of sleeved specimens using an explicit impact code (EPIC). In addition, modifications to the sleeved concept geometry (tapered and capped core) are also explored numerically as well as the sleeve/core sliding friction coefficient.


1977 ◽  
Vol 9 (9) ◽  
pp. 1045-1048
Author(s):  
G. N. Tret'yachenko ◽  
B. S. Karpinos ◽  
L. E. Kiyashko

Author(s):  
Nаtalya Fidrovska ◽  
Evgen Slepuzhnikov ◽  
Alexsandr Chernyshenko ◽  
Igor Perevoznyk

The article discusses the modernization of the running wheel due to the introduction of an elastic element. The structure, which consists of three layers, the outer ones of which consist of strong steel material, and the middle layer consists of low-strength lightweight aggregate, which can significantly reduce dynamic forces, vibrations and shocks, which increases the reliability of cargo transportation. Calculations have shown that the stress state of a wheel with an elastic insert is less than that of an old-design travel wheel. The decrease in force and elastic factors in the travel wheel, which has an elastic insert, is explained by the fact that the use of an elastic ring leads to an increase in the bending stiffness of the outer ring of the shell. The obtained solution to the problem of the strength of a three-layer structure makes it possible to determine the stresses in the shell depending not only on its geometric parameters, but also on the shear modulus of the filler, which improves the reliability of the design and operation of such structures. Theoretical studies of the stress state of a three-layer cylindrical structure, taking into account the shear energy of the filler, makes it possible to assess the strength of such a structure and give certain recommendations for its use. Experimental studies that were carried out on an operating overhead crane fully confirmed a very significant reduction in oscillatory processes in travel wheels. The level of vibration acceleration in the vertical direction on the modernized drive wheel is almost 3 times less than the level of vibration acceleration on the drive wheel at idle speed of a conventional design.


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