scholarly journals Influence of normal stress on creep in tension and compression of polyethylene and rigid polyvinyl chloride copolymer

1962 ◽  
Vol 2 (4) ◽  
pp. 273-284 ◽  
Author(s):  
D. G. O'Connor ◽  
W. N. Findley
1962 ◽  
Vol 84 (2) ◽  
pp. 237-246 ◽  
Author(s):  
D. G. O’Connor ◽  
W. N. Findley

New apparatus suitable for compression creep tests of slender specimens is described. The apparatus is designed to prevent buckling and to introduce a minimum of friction. Results are reported for tension and compression creep of polyethylene and annealed, unplasticized polyvinyl chloride copolymer at 75 deg F and 50 per cent relative humidity. The stress σ, strain ε, time t data from these tests were found to be describable with reasonable accuracy by the equation ε=ε0′sinhσ/σε+m′tnsinhσ/σm where ε0′, m′, n, σε, and σm are material constants. The results for polyethylene show that the creep in tension and compression were virtually the same. However, the creep in tension was similar but larger than in compression for polyvinyl chloride. These observations are interpreted in terms of the material structure and the influence of the normal stress on active shear planes.


2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Rahul Palaniappan Kanthabhabha Jeya ◽  
Zijian Zhao ◽  
Abdel-Hakim Bouzid

Abstract Similar to many polymer materials, high-density polyethylene (HDPE) and polyvinyl chloride (PVC) show a clear creep behavior, the rate of which is influenced by temperature, load, and time. Most bolted flange joints undergo relaxation under compression, which is caused by the creep of the material. However, the creep property of the two polymers is different under tension and compression loading. Since the sealing capacity of a flanged gasketed joint is impacted by the amount of relaxation that takes place, it is important to properly address and predict the relaxation behavior due to flange creep under compression and thereby reducing the chances of leakage failure of HDPE and PVC bolted flange joints. The main objective of this study is to analyze the compressive creep behavior of HDPE and PVC flanges under normal operating conditions. This is achieved by developing a respective creep model for the two materials, based on their short-term experimental creep test data. Both numerical and experimental simulations of the polymeric flange relaxation behavior are conducted on an NPS 3 class 150 bolted flange joint of dissimilar materials, where one of the flanges is made of HDPE or PVC material and the other one is made of steel SA105. The study also provides a clear picture on how the compression creep data of ring specimen may be utilized for predicating the flange bolt load relaxation over time at the operating temperatures.


2018 ◽  
Vol 7 (4.19) ◽  
pp. 853
Author(s):  
Adel A. Al-Azzawi ◽  
Mustafa S. Shalal

The concrete prepared with Polyvinyl chloride plastics (collected from doors and windows wastes) as recycled coarse aggregates and their concrete engineering properties are studied in the laboratory in this research. The concrete blends have an expected cylinder compressive strength of 28 MPa. In this research, the concrete blends contain plasticcoarse aggregate.The ratio of this aggregate to the total aggregate volume ranges from 0 to 1. The concrete strength properties in tension and compression are greatly affected with the plastic replacement ratio. The blends density reduces with increasing replacement ratio. For low replacement ratio, the effect is practically marginal. It is not acceptable to use ACI 318 code spilt cylinder equation for plasticaggregate concrete with higher replacement ratio  


Author(s):  
T. G. Gregory

A nondestructive replica technique permitting complete inspection of bore surfaces having an inside diameter from 0.050 inch to 0.500 inch is described. Replicas are thermally formed on the outside surface of plastic tubing inflated in the bore of the sample being studied. This technique provides a new medium for inspection of bores that are too small or otherwise beyond the operating limits of conventional inspection methods.Bore replicas may be prepared by sliding a length of plastic tubing completely through the bore to be studied as shown in Figure 1. Polyvinyl chloride tubing suitable for this replica process is commercially available in sizes from 0.037- to 0.500-inch diameter. A tube size slightly smaller than the bore to be replicated should be used to facilitate insertion of the plastic replica blank into the bore.


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