Guide for Recommended Formats for Data Records Used in Computerization of Mechanical Test Data for Metals

10.1520/e1313 ◽  
2000 ◽  
Author(s):  
Keyword(s):  
Test Data ◽  
Mechanical Test

scholarly journals Environmental degradation of composites for marine structures: new materials and new applications

2016 ◽  
Vol 374 (2071) ◽  
pp. 20150272 ◽  
Author(s):  
Peter Davies
Keyword(s):  
Composite Materials ◽  
Test Data ◽  
Environmental Degradation ◽  
Structural Integrity ◽  
Mechanical Test ◽  
Traditional Approach ◽  
Essential Element ◽  
Structural Testing ◽  
Marine Structures

This paper describes the influence of seawater ageing on composites used in a range of marine structures, from boats to tidal turbines. Accounting for environmental degradation is an essential element in the multi-scale modelling of composite materials but it requires reliable test data input. The traditional approach to account for ageing effects, based on testing samples after immersion for different periods, is evolving towards coupled studies involving strong interactions between water diffusion and mechanical loading. These can provide a more realistic estimation of long-term behaviour but still require some form of acceleration if useful data, for 20 year lifetimes or more, are to be obtained in a reasonable time. In order to validate extrapolations from short to long times, it is essential to understand the degradation mechanisms, so both physico-chemical and mechanical test data are required. Examples of results from some current studies on more environmentally friendly materials including bio-sourced composites will be described first. Then a case study for renewable marine energy applications will be discussed. In both cases, studies were performed first on coupons at the material level, then during structural testing and analysis of large components, in order to evaluate their long-term behaviour. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’.

scholarly journals A Generalized Method for the Analysis of Planar Biaxial Mechanical Data Using Tethered Testing Configurations

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Will Zhang ◽  
Yuan Feng ◽  
Chung-Hao Lee ◽  
Kristen L. Billiar ◽  
Michael S. Sacks
Keyword(s):  
Stress Tensor ◽  
Test Data ◽  
Soft Tissues ◽  
Mechanical Test ◽  
Specimen Geometry ◽  
Parameter Determination ◽  
Biaxial Test ◽  
Cauchy Stress ◽  
Cauchy Stress Tensor ◽  
Thin Sections

Simulation of the mechanical behavior of soft tissues is critical for many physiological and medical device applications. Accurate mechanical test data is crucial for both obtaining the form and robust parameter determination of the constitutive model. For incompressible soft tissues that are either membranes or thin sections, planar biaxial mechanical testing configurations can provide much information about the anisotropic stress–strain behavior. However, the analysis of soft biological tissue planar biaxial mechanical test data can be complicated by in-plane shear, tissue heterogeneities, and inelastic changes in specimen geometry that commonly occur during testing. These inelastic effects, without appropriate corrections, alter the stress-traction mapping and violates equilibrium so that the stress tensor is incorrectly determined. To overcome these problems, we presented an analytical method to determine the Cauchy stress tensor from the experimentally derived tractions for tethered testing configurations. We accounted for the measured testing geometry and compensate for run-time inelastic effects by enforcing equilibrium using small rigid body rotations. To evaluate the effectiveness of our method, we simulated complete planar biaxial test configurations that incorporated actual device mechanisms, specimen geometry, and heterogeneous tissue fibrous structure using a finite element (FE) model. We determined that our method corrected the errors in the equilibrium of momentum and correctly estimated the Cauchy stress tensor. We also noted that since stress is applied primarily over a subregion bounded by the tethers, an adjustment to the effective specimen dimensions is required to correct the magnitude of the stresses. Simulations of various tether placements demonstrated that typical tether placements used in the current experimental setups will produce accurate stress tensor estimates. Overall, our method provides an improved and relatively straightforward method of calculating the resulting stresses for planar biaxial experiments for tethered configurations, which is especially useful for specimens that undergo large shear and exhibit substantial inelastic effects.

scholarly journals State of the art methods to post-process mechanical test data to characterize the hot deformation behavior of metals

2021 ◽  
Vol 13 (11) ◽  
pp. 168781402110610
Author(s):  
Shahin Khoddam ◽  
Soheil Solhjoo ◽  
Peter D Hodgson
Keyword(s):  
Test Data ◽  
Mechanical Test ◽  
Indirect Measurement ◽  
Data Conversion ◽  
Post Processing ◽  
Data Types ◽  
Flow Curves ◽  
Characterization Methods ◽  
Post Process ◽  
Processing Theory

Materials engineering and science rely heavily on the indirect measurement of plastic stress and strain by post-processing of mechanical test data, including tension, torsion, and compression test. There is no consensus among researchers regarding the best test or the post-processing theory nor do adequate standards exist on the characterization methods. The tests are typically performed as customized tests, discrepancies exist in the flow curves obtained by different methods and the chosen mechanical test. More critically, the curves are dominantly treated (perceived) as a set of measured data rather than calculated values. The plasticity-based calculated flow curves and their gradients are, in turn, the basis for several second-tier indirect measurements, such as stacking fault energy and recrystallization. Such measurements are quite prone to errors due to oversimplified post-processing of the tests’ data and can only be experimentally verified in a qualitative or in an average fashion. Therefore, their findings are highly restricted by the limitations of each test, data type and post-processing method, and should be used carefully. This review examines some of the most commonly used data conversion methods and some recent developments in the field followed by recommendations. It will highlight the need to develop test rigs that can provide new data types and to provide advanced post-processing techniques for the indirect measurement.

scholarly journals Zechstein Salt Denmark. Salt Research Project EFP-81. Volume III: Fabric analysis of domal rock salt

1984 ◽  
Vol 1 (3) ◽  
pp. 1-100
Author(s):  
Jørgen Gutzon Larsen ◽  
Per Lagoni
Keyword(s):  
Statistical Analysis ◽  
Test Data ◽  
Rock Salt ◽  
Mechanical Test ◽  
Research Project ◽  
Fabric Analysis ◽  
Zechstein Salt

Volume III is part of four volumes elaborated in the course of Salt Research Project EFP-81. The volume deals with petrofabric analyses of rock salt related to mechanical test data and statistical analysis of these data.

The Mechanism of Internal Stress Superplasticity

1990 ◽  
Vol 196 ◽  
Author(s):  
B. Derby
Keyword(s):  
Thermal Cycling ◽  
Internal Stress ◽  
Metal Matrix Composites ◽  
Plastic Flow ◽  
Test Data ◽  
Metal Matrix ◽  
Mechanical Test ◽  
Matrix Composites ◽  
External Stresses ◽  
Current Mechanism

ABSTRACTThe phenomenon of internal stress superplasticity is reviewed and the theoretical mechanical foundations of current mechanism models of the process examined. These models are shown to be based on two different principles: i.e. a biased internal plastic flow, or an enhanced creep generated by a superposition of internal and external stresses. Mechanical test data is shown to be more consistent with enhanced plasticity models in zinc and metal matrix composites for deformation during thermal cycling.

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