Global stress test

Normally, one accelerated condition has to be part of a global stability testing design. To understand the impact of extreme temperature excursions during shipment, it is recommended to test in addition the product at stress conditions, for example, one batch at 50°C/ambient humidity for 3 months. 

Lohr, S. (2011, March 16). Stress test for the global supply chain. The New York Times, Business Day. 

Micro yield shear stress and uniaxial hardening behaviour are usually measured by global compressive tests made on material samples. This process gives average values over the section of the sample. Therefore, to be relevant, this test must be made on uniform samples. Two uniform samples (A... 

The characterisation of the mechanical behaviour profile requires a local measurement that can not be obtained by a global compressive test. Nano indentaticHi test has thoi been used to stress locally the mata-ial. Expo-iments have been conducted on Nano-instruments model II nano-indento, that has been fitted with a spherical diamond tip of 105 pm radius. This apparatus, (schematically described in figure 2) allows the simultaneous record of the applied load W (ranging form 0 to 700 mN) and of the displacement of the indentation head. El Ghazal... 

Some of the NPP models are based on the color imagery and some are not. In the latter, phytoplankton growth is estimated from coupled global circulation and biogeo-chemical models in which water motion controls nutrient availability. The water motion is controlled by climatic factors, such as temperature gradients and wind stress. The latest effort to compare model outputs was conducted with 31 different models and foimd that global estimates for a test year (1998) differed by as much as a factor of 2 The mean results from this model intercalibration experiment are shown in Table 23.7. 

There are critical needs with regard to protecting the environment (Medina, 1996). The use of solvents introduces stresses on ecosystems, ultimately on the global level. More testing for acute human toxicity is needed, but increasingly, researchers will strive to include effects on entire ecosystems, and long-term, multigenerational effects on fertility, reproductive quality, and hormonal functions. Any solvent that leads to environmental problems, that can be persistent, toxic, and bioaccumulative, or any combination of these three attributes, needs to be evaluated (Division, 1996). This... 

Based on the characterization of the bentonite and on the details of the process of test installation, a thermo-hydro-mechanical model for the bentonite barrier and the heaters was to be prepared. Using this model, the thermo-hydro-mechanical response of the bentonite barrier as a result of the heat released by the heaters and the hydration from the host rock was required. Local field variables such as temperature, relative humidity, pore water pressure, stresses and displacements, as well as global... 

This chapter presents both experimaital and finite element approaches that are commonly used to assist in the design and failure analysis of composite bolted joints. The work presented mostly stems from the authors work in the field over the past decade. Results from both local (i.e. detailed) finite element and global (Le. efficient) closed form and finite element approaches are presented, and expmmental results from the open literature are used to both calibrate and validate the modelling procedures. The primary variable under consideration is bolt-hole clearance, which is chosen as it induces significant three-dimensional stresses into the joint, and significandy alters the bolt-load distribution in multi-bolt joints, and so provides a rigorous test case for analysis. 

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