Long-Term Behaviour of GFRP Pipes: Reducing the Prediction Test Duration

2009 ◽  
Author(s):  
Hugo Faria
Keyword(s):  
Estimation Error ◽  
Standard Test ◽  
Test Duration ◽  
Test Procedures ◽  
Residual Properties ◽  
Piping Systems ◽  
Glass Fibre Reinforced Plastic ◽  
Prediction Test ◽  
Glass Fibre Reinforced

The certification of glass-fibre reinforced plastic (GFRP) piping systems is regulated by normative standards in which test series of 10000 hours are required to estimate the residual properties at the end of the expected life (normally, 50 years). In this paper, the possibility to reduce the tests duration, maintaining an equivalent prediction of long-term properties, is discussed. Experimental results from standard test procedures conducted on GFRP pipes of four different types and respective data analysis support this possibility. The estimation error when using only data from shorter tests is consistently less than 10% if compared to the standard methods.

scholarly journals Alkali Release from Aggregates in Long-Service Concrete Structures: Laboratory Test Evaluation and ASR Prediction

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1393 ◽  
Author(s):  
Mario Berra ◽  
Teresa Mangialardi ◽  
Antonio Paolini
Keyword(s):  
Calcium Hydroxide ◽  
Concrete Structures ◽  
Weight Ratio ◽  
Standard Test ◽  
Test Method ◽  
Test Duration ◽  
Alkali Extraction ◽  
Proposed Model ◽  
Leaching Solution

This paper proposes a simple model for predicting the development of deleterious expansion from alkali-silica reaction (ASR) in long-service concrete structures. This model is based on some composition and reactivity parameters related to ASR, including the long-term alkali contribution by aggregates to concrete structures. This alkali contribution was estimated by means of a laboratory extraction test, appositely developed in this study in order to maximize the alkali extraction within relatively short testing times and with low leaching solution/aggregate ratios. The proposed test is a modification of the Italian Standard test method UNI 11417-2 (Ente Nazionale Italiano di Normazione) and it consists of subjecting an aggregate sample to leaching with saturated calcium hydroxide solution in a laboratory autoclave at 105 °C. Nine natural ASR-susceptible aggregates (seven sands and two coarse aggregates) were tested and the following optimized test conditions were found: leaching solution/aggregate weight ratio = 0.6; solid calcium hydroxide/aggregate weight ratio = 0.05; test duration = 120 h. The results of the optimized alkali extraction tests were used in the proposed model for predicting the potential development of long-term ASR expansion in concrete dams. ASR predictions congruent with both the field experience and the ASR prevention criteria recommended by European Committee for Standardization Technical Report CEN/TR 16349:2012 were found, thus indicating the suitability of the proposed model.

Analysis of Stresses and Strains in Packed Stuffing-Boxes

2014 ◽  
Author(s):  
Mehdi Kazeminia ◽  
Abdel-Hakim Bouzid
Keyword(s):  
Design Procedure ◽  
Standard Test ◽  
Packing Material ◽  
Test Procedures ◽  
Analytical Methodology ◽  
Packing Materials ◽  
Standard Design ◽  
Packing Rings ◽  
Leak Tightness ◽  
Side Walls

Packed stuffing-boxes are mechanical sealing systems that are extensively used in pressurized valves and pumps. Yet there is no standard design procedure that could be used to verify their mechanical integrity and leak tightness. It is only recently that standard test procedures to qualify the packing material have been suggested for adoption in both North America and Europe. While the packing contact stress with the side walls is predictable using existing models there is no analytical methodology to verify the stresses and strains in the stuffing-box housing. This paper presents an analytical model that analyzes the stresses and strains of all the stuffing box components including the packing rings. The developed model will be validated both numerically using FEM and experimentally on an instrumented packed stuffing box rig that is specially designed to test the mechanical and leakage performance of different packing materials.

scholarly journals Seawater effects on static loads and interlayer cracking performance for polyvinyl chloride foam-cored sandwich composites

2018 ◽  
Vol 10 (11) ◽  
pp. 168781401880734
Author(s):  
Jian He ◽  
Dongyuan Xie ◽  
Qichao Xue ◽  
Yangyang Zhan
Keyword(s):  
Energy Release ◽  
Polyvinyl Chloride ◽  
Glass Fibre ◽  
Critical Energy ◽  
Bending Tests ◽  
Rate Dependent ◽  
Reinforced Plastic ◽  
Glass Fibre Reinforced Plastic ◽  
Glass Fibre Reinforced ◽  
Cantilever Bending

The diffusion influence of seawater on the static and interlayer cracking properties of a polyvinyl chloride foam sandwich structure is investigated in this study. After soaking specimens in seawater for various durations, various comparison tests are performed to investigate the effects of seawater. Compression tests for H60 and H200 polyvinyl chloride foam specimens are conducted to study strength and modulus degradation, and the results show that immerging time and temperature have significant effects on polyvinyl chloride foam properties. Tensile tests for glass-fibre-reinforced plastic panels, four-point bending tests and double cantilever bending tests for polyvinyl chloride foam sandwich specimens are also performed. The results show that seawater immerging treatment has a noticeable influence on glass-fibre-reinforced plastic tensile properties and interlayer critical energy release rate values, but has almost no effect on bending properties of foam sandwich specimen. Furthermore, a rate-dependent phenomenon is observed in double cantilever bending tests, in which higher loading rate will lead to larger critical energy release values. Numerical simulation is also performed to illustrate the cracking process of double cantilever bending tests and shows a certain accuracy. The simulation also demonstrates that the viscoelasticity of foam material after immerging treatment results in the rate-dependent characterization of double cantilever bending tests.

scholarly journals Towards Standardising SHPB Testing - A Round Robin Exercise

2018 ◽  
Vol 183 ◽  
pp. 02027
Author(s):  
Reuben Govender ◽  
Muhammad Kariem ◽  
Dong Ruan ◽  
Rafael Santiago ◽  
Dong Wei Shu ◽  
...  
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Pure Copper ◽  
Round Robin ◽  
Standard Test ◽  
Test Method ◽  
Hopkinson Pressure Bar ◽  
Test Procedures ◽  
Draft Standard ◽  
Shpb Test ◽  
Pressure Bar

The Split Hopkinson Pressure Bar (SHPB) test, while widely utilised for high strain rate tests, has yet to be standardised. As an exploratory step towards developing a standard test method or protocol, a Round Robin test series has been conducted between four institutions: (i) Swinburne University of Technology, Australia (ii) University of São Paulo, Brazil, (iii) University of Cape Town, South African and (iv) Nanyang Technological University, Singapore. Each institution prepared specimens from a metallic material, and provided batches of specimens from their chosen material to the other institutions. The materials utilised in this round of testing were commercially pure copper and aluminium, magnesium alloy and stainless steel (316 grade). The intent of the first exercise is to establish the consistency of SHPB test results on nominally identical specimens at comparable elevated strain rates, conducted by different laboratories following notionally similar test procedures with some freedom in data processing. This paper presents and compares the results of the first batch of tests for copper, identifying variations between results from different laboratories. The variation between different laboratories’ results for copper is suffciently small that there is confidence in the potential to develop a draft standard in future.

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