scholarly journals BIAXIAL AND UNIAXIAL STRESS RELAXATION AND CREEP PROPERTIES OF COATED PLAIN-WEAVE FABRICS USED FOR MEMBRANE STRUCTURES

Author(s):  
HIROKAZU MINAMI ◽  
HIROSHI TOYODA ◽  
SHINYA SEGAWA
1982 ◽  
Vol 11 (4) ◽  
pp. 310-327
Author(s):  
H. Irokazu ◽  
M. Inami ◽  
Yoshio Nakahara

Methods for analysing coated plain-weave fabric which has properties of nonlinear elasticity have not yet been satisfactorily developed. In this paper, a method which is promis ing for use in engineering applications like the strength analysis of membrane structures is presented. The finite element method using a rectangular element consisting of plain-weave fabric and coating material which is assumed to be an isotropic elastic plate of plane stress is applied to the method. Verification of the me thod is made by using uniaxial stress-strain responses. A square piece of coated plain-weave fabric with a square hole in it is analyzed as an example of application of the present method. Key Words: coated plain-weave fabrics; finite element method; nonlinearly elastic biaxial response; geometrically nonlinear prob lem ; incremental approach.


2002 ◽  
Vol 124 (2) ◽  
pp. 207-214 ◽  
Author(s):  
Keiji Nakacho

Stress-relief annealing (SR treatment) is often applied to relieve welding residual stresses in the fabrication process of pressure vessels, etc. This study aims at development of an efficient method as simple as hand calculation to estimate reduction of residual stresses of a very thick welded joint by SR treatment. In the first report, an estimating method was developed for relaxation tests, in uniaxial stress state, at changing and constant temperatures because the stress relaxation phenomenon may be considerably similar to that observed in the SR treatment of a joint. In the second report, the stresses relaxed by SR treatment in a very thick welded joint were analyzed accurately by the finite element method based on thermal elastic-plastic creep theory. The characteristics of the changes of the welding residual stresses in multiaxial stress state were studied in detail for further development of the estimating method to SR treatment of a very thick welded joint, of which the stress state and boundary condition are very complex. In the third report, the estimating equations in multiaxial stress states were developed for the stress relaxation phenomenon in the thick welded joints, based on the foregoing characteristics. In this report, the applicability of the simple estimating method is investigated for SR treatment of the thick welded joint, by comparing the estimated results with the accurate ones obtained by FEM.


Author(s):  
Yaoliang Zhu ◽  
Jin Yu ◽  
Xianqi Zhou ◽  
Zhehao Yang ◽  
Xin Tang ◽  
...  

2020 ◽  
Vol 8 (8) ◽  
pp. 603
Author(s):  
Hua Huang ◽  
Yaoqiang Xian ◽  
Wei Zhang ◽  
Mengxue Guo ◽  
Kun Yang ◽  
...  

Lightweight cable–membrane structures can span large distances and undertake aesthetically pleasing shapes. They are widely used for roofs and modern structural canopies and in the aerospace industry for large on-board antenna reflectors that are to be deployed in space. This paper studies a wind-induced vibration under different cable stress relaxation conditions based on the wind load time-history to obtain the dynamic behavior of such a structure. Particularly, the focus is put upon its wind resistance in the event of stress relaxation. This research can provide an important reference for the design of wind resistance, damage assessment, and emergency maintenance for the spoke-wise cable–membrane structure (SCMS).


2000 ◽  
Vol 123 (1) ◽  
pp. 70-74 ◽  
Author(s):  
F. V. Ellis ◽  
D. R. Sielski ◽  
R. Viswanathan

A research project was conducted to develop and validate an improved, analytical life prediction method for high-temperature turbine and valve studs/bolts. The life prediction method used the two-parameter creep equation, an incremental calculation procedure and a strain hardening flow rule. The failure criterion was an accumulated inelastic or creep strain limit of 1 percent. The life prediction procedure recommends the use of the service history of operating temperature, number/stress level of tightenings, cycle time, etc., to calculate the stress relaxation behavior. Life assessment uses the measured bolt length to calculate the accumulated creep strain. The link between the current condition, i.e., accumulated creep strain, and the remaining creep life, i.e., time to accumulate 1 percent strain, is obtained by a prediction of the future creep strain accumulation under the intended loading cycle(s) imposed during future operation. In order to validate the approach, the calculated results were compared to the results of uniaxial stress relaxation testing, bolt model testing, and service experience. The analytical procedure coupled with other industry wide NDE and measurement procedures is expected to provide broad guidelines to utilities for bolting life assessment.


2013 ◽  
Vol 709 ◽  
pp. 84-88 ◽  
Author(s):  
Lu Yu Zhou ◽  
Xian Bo Li

In order to analyze the creep properties of UHMWPE multifilament and aramid multifilament, four-element model and Matlab software were used to get creep fitting curve, the corresponding mechanical fitting equation and microscopic parameters. The creep properties of the two kinds of multifilament were discussed by microscopic parameters. At the same time, the tensile and relaxation performance of UHMWPE multifilament and aramid filament were studied. Compared with aramid multifilament, UHMWPE multifilament has higher strength, better elongation, lower creep resistance and obvious the phenomenon of stress relaxation. This article will provide some basic performance reference to the application of UHMWPE multifilament.


1983 ◽  
Vol 9-9 (8-9) ◽  
Author(s):  
Tomasz Sterzynski ◽  
Marek Szostak ◽  
Adam Nowak

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