A simplified orthotropic formulation of the viscoplasticity theory based on overstress

An orthotropic, small strain viscoplasticity theory based on overstress is presented. In each preferred direction the stress is composed of time (rate) independent (or plastic) and viscous (or rate dependent) contributions. Tension-compression asymmetry can depend on direction and is included in the model. Upon a proper choice of a material constant one preferred direction can exhibit linear elastic response while the other two deform in a viscoplastic manner

Cyclic uniaxial and biaxial hardening of type 304 stainless steel modeled by the viscoplasticity theory based on overstress

The isotropic theory of viscoplasticity based on overstress does not use a yield surface or a loading and unloading criterion. The inelastic strain rate depends on overstress, the difference between the stress and the equilibrium stress, and is assumed to be rate dependent. Special attention is paid to the modeling of elastic regions. For the modeling of cyclic hardening, such as observed in annealed Type 304 stainless steel, and additional growth law for a scalar quantity which represents the rate independent asymptotic value of the equilibrium stress is added. It is made to increase with inelastic deformation using a new scalar measure which differentiates between nonproportional and proportional loading. The theory is applied to correlate uniaxial data under two step amplitude loading including the effect of further hardening at the high amplitude and proportional and nonproportional cyclic loadings. Results are compared with corresponding experiments

Is spirituality the essence of sustainability?

What is spirituality? Does it have a place in contemporary life where corporate systems and material driven lifestyles dominate? It would seem that many people are not comfortable talking about spirituality in public for fear of raising controversy. That in itself suggests that rather than being insignificant, spirituality is an important element of everyday life. To explore this further, I have developed what I term a ‘Connectivity Matrix’ to enable the representation of the great diversity of opinions, interpretations, and experiences regarding spirituality in today’s world. I am currently trialling this matrix through my doctoral fieldwork. It places spirituality as one of the pillars of everyday life alongside the other pillars of community, corporate systems, and nature. This paper proposes that the commonly used concepts of the ‘Triple Bottom Line’ and the ‘Four Pillars of Sustainability’ are incomplete without a spirituality pillar. Using the Connectivity Matrix, a series of semi-structured interviews and workshops have been conducted with people involved in various areas of sustainability in Western Australia. This paper uses recent scientific findings as well as established and new theories relating to mainstream spirituality to analyse perceptions, experiences, and understandings in relation to the role of spirituality in today’s society and its impact on sustainability

The viscoplasticity theory based on overstress applied to the modeling of a nickel base superalloy at 815 C

Short term strain rate change, creep and relaxation tests were performed in an MTS computer controlled servohydraulic testing machine. Aging and recovery were found to be insignificant for test times not exceeding 30 hrs. The material functions and constants of the theory were identified from results of strain rate change tests. Numerical integration of the theory for relaxation and creep tests showed good predictive capabilities of the viscoplasticity theory based on overstress

Spirituality and environmental sustainability: Developing community engagement concepts in Perth, Western Australia

This research trials three concepts: The Connectivity Matrix; Five Dimensions; and Combined View. These engage communities of diverse backgrounds in conversation about their corporeal and metaphysical relationship with nature and spirituality: to ascertain the link between these phenomena in decision-making; and to analyse the influence of these experiences on the biophysical world. The findings identify three spiritual modalities and their impacts on the dichotomy of self-interest and selflessness, which in turn affect environmental sustainability

Five dimensions of community

The Five Dimensions of Community concept places culture and heritage within the context of planet Earth and the cosmos. This allows space to discover what universal wonder means for people of different backgrounds and to share moments where natural experiences have taken your breath away and provided new sights. Through a greater awareness of the elements of the Five Dimensions of Community we can better engage in the interconnectedness between heritage and culture, the built and natural environment, corporate living and spirituality. This paper proposes that in order to contextualize our cultural heritage, we need to go beyond the triple bottom line and the four pillars sustainability frameworks that seem to separate us from the rest of the world, and look for the spiritual links that connect us to each other, the Earth and the universe so that new or renewed sustainable traditions can emerge

Revolutionizing fiber-reinforced thermoplastic composite recycling: the LightCycle project's journey towards energy-efficient upcycling and quality material regeneration

The recycling of fiber-reinforced thermoplastic composites presents a significant challenge, leading to high waste generation and limited reuse options. The LightCycle project aims to address this issue by developing an energy-efficient and circular method for upcycling glass fiber composite waste and recycling polypropylene (PP). This work focuses on analyzing the material properties of PP regenerates (rPP) from post-consumer waste in Austria, as well as the compounds derived from it and glass fiber-reinforced thermoplastic composites. The goal is to establish material expertise and determine acceptable quality ranges for the LightCycle process. Thermal and rheological material data measurements to analyze the material input quality and the fluctuation range suggest a stable LightCycle process with a wide process window. Furthermore, the analyzis of first compounds with rPP and two different types of shredded glass fiber reinforced thermoplastic composites highlights the significant impact of the type of flake used on the compound's properties

Fabrication of high temperature surface acoustic wave devices for sensor applications

Surface acoustic devices have been shown to be suitable not only for signal processing but also for sensor applications. In this paper high temperature surface acoustic wave devices based on gallium orthophosphate have been fabricated, using a lift-off technique and tested for high frequency applications at temperatures up to 600 ºC. The measured S-parameter (S11) has been used to study the mass loading effect of the platinum electrodes and turnover temperature of GaPO4 with a 5? cut. The analysis of these results shows that the mass loading effect can be used to predict the desired resonant frequency of the SAW devices. Also two different adhesion layers for Pt metallisation were studied. Our results show that Zirconium is a more suitable under layer than Titanium