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The purpose of this paper is to present a methodology to assess material damage parameters for ductile crack initiation and growth ahead of a crack/notch tip in high hardening steel like AISI type 316L(N) stainless steel.

Ductile damage parameter and far field J-integral have been obtained from standard FEM analysis for a crack/notch tip undergoing large plastic deformation and resulting in crack initiation/growth. In conjunction with experimental results, the damage variable for low strength and high hardening material has been derived in terms of continuum parameters: equivalent plastic strain (ε_eq) and stress triaxiality (φ). The material parameters for damage initiation and growth in 316LN SS have been evaluated from tensile and fracture tests. With these material tensile/fracture parameters as input, elastic-plastic eXtended Finite Element Method (X-FEM) simulations were carried out on compact tension (CT) specimen geometry under varying initial stress triaxiality conditions.

The material parameters for damage initiation and growth have been assessed and calibrated by comparing the X-FEM predicted load-displacement responses with the experimental results. It is observed that the deviations in the predicted load values from the experimental data are within 6 percent for specimens with a/W=0.39, 0.55, 0.64, while for a/W=0.72, it is 17 percent.

The present study is a part of developing methods to obtain calibrated material damage parameters for crack growth simulation of components made of AISI 316L(N) stainless steel. This steel is used for fast breeder reactor-based power plant being built at Kalpakkam, India.

The purpose of this paper is to present a methodology to predict initial crack growth behavior of crack or notch like stress raisers in AISI 316L(N) stainless steel material subjected to monotonic loading condition.

The methodology for critical crack blunting corresponding to crack initiation in crack or notch like stress raisers is based on critical plastic strain (Epc) at a characteristic distance (lc), where uniform strain (Eu) is considered as Epc and two grain diameter is considered as lc. Further crack growth is based on parabolic crack tip opening displacement (CTOD) scheme established based on coupled experimental and FEM analysis of compact tension (CT) specimen subjected to mode-I loading condition. The FEM predicted load-displacement plots is compared with experimental result of CT specimens with different a/W ratios. It has shown that the proposed methodology could account initial crack blunting appropriately and predict the fracture load and load-displacement plots for initial crack growth regime.

The results show that for crack growth with near straight crack front, experimental data from a CT specimen of particular a/W ratio coupled with plane strain 2D FEM analysis could predict load vs displacement plots for different a/W ratios when initial crack blunting is accounted appropriately with a local damage model.

The present study is a part of developing methods to analyse fracture behavior of AISI 316L(N) SS material components used for fast breeder reactor-based power plant being built at Kalpakkam, India.

Attempts to transfer Western management theories without considering the host's cultural value system is a prescription for failure. While conceptual frameworks for understanding cultural differences exist, such as the ones developed by Hofstede and Hall, we know little about which managerial practices are relevant in what cultural settings. Adopting the view that the effectiveness of different management behaviors depends on the culture in which they are practiced, this paper develops various propositions that match specific managerial behaviors with cultural work values. The matching of managerial behaviors with cultural values has a wide range of applications in overseas selection decisions and training programs.

Purpose – This chapter offers an integrative review of psychological and neurobiological differences between younger and older adults that might impact economic behavior. Focusing on key health economic challenges facing the elderly, it offers perspectives on how these psychological and neurobiological factors may influence decision-making over the life course and considers future interdisciplinary research directions.

Methodology/approach – We review relevant literature from three domains that are essential for developing a comprehensive science of decision-making and economic behavior in aging (psychology, neuroscience, and economics), consider implications for prescription drug coverage and long-term care (LTC) insurance, and highlight future research directions.

Findings – Older adults face many complex economic decisions that directly affect their health and well-being, including LTC insurance, prescription drug plans, and end of life care. Economic research suggests that many older Americans are not making cost-effective and economically rational decisions. While economic models provide insight into some of the financial incentives associated with these decisions, they typically do not consider the roles of cognition and affect in decision-making. Research has established that older age is associated with predictable declines in many cognitive functions and evidence is accumulating that distinct social motives and affect-processing profiles emerge in older age. It is unknown how these age differences impact the economic behaviors of older people and implies opportunities for path-breaking interdisciplinary research.

Originality/value of the chapter – Our chapter looks to develop interdisciplinary research to better understand the causes and consequences of age-related changes in economic decision-making and guide interventions to improve public programs and overall social welfare.

Social justice, true social justice, must be sought and obtained. Once obtained institutionally, social justice is manifested by a desire to maintain equality in otherwise diverse environments. The irony of social justice is that historically and currently, it is a societal ideal that is difficult to achieve. The uniqueness of every human being should be recognized in institutions that emphasize social justice, as being a strength. However, being that the nature of human beings is to be comfortable with fellow human beings who act and look similar to themselves, until made aware of our own hidden biases, social justice cannot prevail.

As Piderit (2000) points out, much of the work on resistance to change borrows from the field of mechanics, conceptualizing resistance as a force that slows or stops motion and increases the energy and work required to alter the rate and magnitude (distance) of movement. These ideas are evident in Lewin's (1947) work on resistance in which he conceptualizes a quasi-stationary equilibrium as a dynamic balance between a field of forces driving for movement in one direction and a field of forces driving for movement in the opposite direction; movement in the equilibrium occurs only through increases and decreases in these forces.

The purpose of this paper is to determine local properties in a coarse grain zone of 10 mm thick butt welded joints made of structural S355 and high strength S960 steels. Metallographic analyses showed that the width of the investigated zone for both S355 and S960 weldments was too small for direct sampling. Therefore, samples with reproduced microstructure were manufactured by heat treatment taking into account chemical composition and cooling conditions of weldments.

The basis for the heat treatment was the time-temperature-transition (TTT) curve, whose shape is defined by welding and cooling parameters. In this study the TTT curve was determined experimentally during welding as well as numerically simulated using SYSWELD program. The work pieces were heat-treated according to the TTT curves using thermomechanical treatment simulator and evaluated in terms of microstructure and micro hardness distribution. Finally, the secondary specimens were manufactured and investigated in monotonic tensile tests.

The presented approach allows for the determination of the local properties of welded joints. In this study mechanical properties (stress-strain curves) of heat affected zone (HAZ) were successfully estimated using samples with reproduced microstructure. Furthermore, it was found out that the chemical composition in the HAZ was not influenced by the welding process. Thus, the HAZ microstructure can be successfully reproduced using base material. Additionally, the paper contains recommendations for simulation of the local microstructure and suggestions for the evaluation of the obtained results.

The advantage of the proposed approach is the enlargement of the material volume with homogeneous microstructure so that different local properties like toughness, fatigue behavior, crack propagation or crashworthiness can be analyzed, what is technically infeasible for the weldments with small HAZ.

An experimental investigation for developing structure-property correlations of hot-rolled E410 steels with different carbon contents, i.e. 0.04wt.%C and 0.17wt.%C metal active gas (MAG) and cold metal transfer (CMT)-MAG weldments was undertaken.

Mechanical properties and microstructure of MAG and CMT-MAG weldments of two E410 steels with varying content of carbon were compared using standardized mechanical testing procedures, and conventional microscopy.

0.04wt.%C steel had strained ferritic and cementite sub-structures in blocky shape and large dislocation density, while 0.17wt.%C steel consisted of pearlite and polygonal ductile ferrite. This effected yield strength (YS), and microhardness being larger in 0.04wt.%C steel, %elongation being larger in 0.17wt.%C steel. Weldments of both E410 steels obtained with CMT-MAG performed better than MAG in terms of YS, ultimate tensile strength (UTS), %elongation, and toughness. It was due to low heat input of CMT-MAG that resulted in refinement of weld metal, and subzones of heat affected zone (HAZ).

A substantial improvement in YS (∼9%), %elongation (∼38%), and room temperature impact toughness (∼29%) of 0.04wt.%C E410 steel is achieved with CMT-MAG over MAG welding. Almost ∼10, ∼12.5, and ∼16% increment in YS, %elongation, and toughness of 0.17wt.%C E410 steel is observed with CMT-MAG. Relatively low heat input of CMT-MAG leads to development of fine Widmanstätten and acicular ferrite in weld metal and microstructural refinement in HAZ subzones with nearly similar characteristics of base metal.

A physically-based elasto-viscoplastic constitutive model is proposed to examine the size effects of the precipitate and blocks on the creep for martensitic heat-resistant steels with both the dislocation creep and diffusional creep mechanisms considered.

The model relies upon the initial dislocation density and the sizes of M₂₃C₆ carbide and MX carbonitride, through the use of internal variable based governing equations to address the dislocation density evolution and precipitate coarsening processes. Most parameters of the model can be obtained from existing literature, while a small subset requires calibration. Based on the least-squares fitting method, the calibration is successfully done by comparing the modeling and experimental results of the steady state creep rate at 600° C across a wide range of applied stresses.

The model predictions of the creep responses at various stresses and temperatures, the carbide coarsening and the dislocation density evolution are consistent with the experimental data in literature. The modeling results indicate that considerable effect of the sizes of precipitates occurs only during the creep at relatively high stress levels where dislocation creep dominates, while the martensite block size effect happens during creep at relatively low stress levels where diffusion creep dominates. The size effect of M₂₃C₆ carbide on the steady creep rate is more significant than that of MX precipitate.

The present study also reveals that the two creep mechanisms compete such that at a given temperature the contribution of the diffusion creep mechanism decreases with increasing stress, while the contribution of the dislocation creep mechanism increases.

The purpose of this study is to extract the response of the simultaneous low-velocity impact of multiple impactors on a porous functionally graded (FG) aluminum plate.

To design a porous FG structure, a series of functions are applied using the porosity coefficient, and mechanical properties including Young’s modulus, shear modulus and the density of the porous structure are presented as a function of the axis placed in the direction of the plate thickness. The first-order shear deformation theory of the plate is used. To simulate the contact process between each impactor and the plate, a nonlinear Hertz contact force is considered for that impactor independently.

ABAQUS finite element software is used for the verification process of the theorical equations. The effects of porous function type, radius and initial velocity of impactor are investigated for the simultaneous impact of five impactors on porous FG aluminum plate with a simply supported boundary condition. Histories of contact force and displacement of the impactor placed in the center of the beam are analyzed in detail with the changes of the mentioned parameters.

Due to the advantages of porous aluminum plate such as high energy absorption and low weight, such structures may be subjected to the simultaneous impact of multiple impactors, which is studied in this research.