Multiscale particle-in-cell modelling for advanced high strength steels

Advanced High Strength Steels (AHSS) offer outstanding characteristics for efficient and economic use of steel. The unique features of AHSS are direct result of careful heat treatment that creates martensite in the steel microstructure. Martensite and carbon content in the microstructure greatly affects the mechanical properties of AHSS, underlining more importance on microstructural discontinuities and their multiphase characteristics. In this paper, we present the Multiscale Particle-In-Cell (MPIC) method for microstructural modelling of AHSS. A specific particle method [1] usually used in fluid mechanics is adapted and implemented in a parallel multiscale framework. This multiscale method is based on homogenisation theories; with Particle-In-Cell (PIC) method in both micro and macroscale, and offers several advantages in comparison to finite element (FE) based formulation. Application of this method to a benchmark uniaxial tension test is presented and compared with conventional FE solutions.

Evaluation of advanced breast cancer multidisciplinary team meatings

Background: Multidisciplinary team meetings (MDMs) have become an important decision-making forum in oncology. These meetings bring together expertise from each relevant field to improve continuity of care and health care outcomes for cancer patients. However there is a lack of evidence demonstrating the effectiveness of MDT meetings in improving cancer patient outcomes. The aim of this study was to explore the perceived value and potential usefulness of multidisciplinary team meetings for patients with advanced breast cancer (ABC).

Methods: ABC MDMs have been conducted since 2002 at two sites of Eastern Health, the second largest health service in Melbourne. Attendees were invited to complete a confidential questionnaire in November 2007 that comprised seven areas aimed to assess their judgment of how well the MDMs have improved patient management, including medical recommendations, psychosocial care, palliative care, community care, and team development. Average scores were calculated for improvement of each area.

Results: A total of 16 (69%) health practitioners participated in the survey, with main representation from nursing (37%), allied health (25%) and medicine (19%). Preliminary results indicate that the broad areas members reported the meeting had improved patient outcomes were in palliative care and medical management. Specific areas of perceived improvement were medical outcomes for patients; early referral to palliative care services; confirmation of diagnosis; referral to supportive care; and appropriateness of palliative care referrals. Conversely, the area that had least improved was community care, as there was no input from GPs or community services other than palliative care. Attendance by GPs and radiologists were considered important for further improving medical outcomes for patients.

Conclusions: This study demonstrates the perceived value of the MDT approach in the care of ABC patients, particularly in improving patient outcomes. The next stage of this research is to conduct a survey of ABC patient satisfaction level.

Assessing advanced life support (ALS) competence: Victorian practices

Advanced life support (ALS) assessments are performed to assess nurses’ abilities to recognize cardiac arrest events, and appropriately manage patients according to resuscitation guidelines. Although there is evidence for conducting assessments after initial ALS education, there is little evidence to guide educators about ongoing assessments in terms of methods, format and frequency.

The aim of this study was to determine methods used by educators to assess ALS skills and knowledge for nurses in Victorian intensive care units. This descriptive study used telephone interviews to collect data. Data were analysed using content analysis. Twenty intensive care educators participated in this study. Thirteen educators (65%) were employed in public hospitals, and 7 educators (35%) worked in private hospitals across 12 Level 3 (60%) and 8 Level 2 (40%) intensive care units.

Results showed all educators used scenarios to assess ALS skills, with 12 educators (60%) including an additional theoretical test. There was variability in ALS assessment frequency, assessment timing in relation to initial/ongoing education, person performing the assessment, and the assessor/participant ratio. Nineteen educators (95%) reported ALS skill competency assessments occurred annually; 1 educator (5%) reported assessments occurred every 2 years. Assessments were conducted during a designated month (n = 10), numerous times throughout the year (n = 8), or on nurses’ employment anniversaries (n = 2). All educators reported many nurses avoided undertaking assessments.

Variability in ongoing ALS assessment methods was evident in Victorian intensive care units with some units applying evidence-based practices. Consideration should be given to the purposes and methods of conducting annual ALS assessments to ensure resources and strategies are directed appropriately. To encourage nurses to retain ALS skills and knowledge, regular practices are recommended as an alternative to assessments. However, further research is required to support this notion.

Pretend play and maternal scaffolding : comparisons of toddlers with advanced development, typical development, and hearing impairment

This study used measures of pretend play and maternal scaffolding to explore and compare the early development of deaf children, typically developing children, and children showing advanced intellectual development. Marked differences were found among the groups in both play development and characteristics of mother-child interactions. In particular, children who scored above 130 IQ at four years of age were found, as toddlers, to have demonstrated significantly advanced pretend play. In addition, the mothers of the high IQ children engaged in scaffolding behaviors involving higher stages of pretend transformations, verbal analogies and world links. The findings are discussed in relation to children's learning in Vygotsky's Zone of Proximal Development, as well as possible implications for future research on early gifted development.

Cyclic deformation of advanced high-strength steels : mechanical behavior and microstructural analysis

The fatigue properties of multiphase steels are an important consideration in the automotive industry. The different microstructural phases present in these steels can influence the strain life and cyclic stabilized strength of the material due to the way in which these phases accommodate the applied cyclic strain. Fully reversed strain-controlled low-cycle fatigue tests have been used to determine the mechanical fatigue performance of a dual-phase (DP) 590 and transformation-induced plasticity (TRIP) 780 steel, with transmission electron microscopy (TEM) used to examine the deformed microstructures. It is shown that the higher strain life and cyclic stabilized strength of the TRIP steel can be attributed to an increased yield strength. Despite the presence of significant levels of retained austenite in the TRIP steel, both steels exhibited similar cyclic softening behavior at a range of strain amplitudes due to comparable ferrite volume fractions and yielding characteristics. Both steels formed low-energy dislocation structures in the ferrite during cyclic straining.

An evaluation of the performance of advanced melded composite joints

Melding is an efficient three step composite joining process that involves the selective cure of composite adherends before the final adhesive joint is created using the adherends own resin system. Melding does not require many of the processes and compromises associated with conventional techniques like adhesive bonding and mechanical fastening.

The Taguchi design of experiments technique was used to optimise three melded joint factors for a unidirectional epoxy prepreg material. The performance of the joint was evaluated using tensile and flexural strength as well as flexural modulus. It was found that not having a step for every ply in the joint was the most influential factor affecting joint performance. This was due to the differing failure modes induced by this factors various levels, which varied the amount of fibre breakage at failure.

Modeling of advanced high strength steels with the realistic microstructure–strength relationships

The objective of the work is to consider the first-order effects of the realistic microstructure morphology in the macroscale modeling of the multiphase Advanced High Strength Steels (AHSS). Instead of using constitutive equations at macroscale, the strength–microstructure relationship is studied in the forms of micromechanical and multiscale models that do not make considerable simplifications with regard to the microscale geometry and topology. The trade-off between the higher computational time and the higher accuracy has been offset with a stochastic approach in the construction of the microscale models. The multiphase composite effects of AHSS microstructure is considered in realistic microstructural models that are stochastically built from AHSS micrographs. Computational homogenization routines are used to couple micro and macroscale and resultant stress–strain relations are compared for models built with the simplified and idealized geometries of the microstructure. The results from this study show that using a realistic representation of the microstructure, either for DP or TRIP steel, could improve the accuracy of the predicted stress and strain distribution. The resultant globally averaged effective stress and strain fields from realistic microstructure model were able to accurately capture the onset of the plastic instability in the DP steel. It is shown that the macroscale mechanical behavior is directly affected by the level of complexities in the microscale models. Therefore, greater accuracy could be achieved if these stochastic realistic microstructures are used at the microscale models.