Optimal Financial Exclusion

We study efficient exclusion policies in a canonical credit model that features both exogenous and strategic default along the equilibrium path. Policies that maximize welfare in a stationary equilibrium implement exclusion for a finite and deterministic number of periods following default. Front-loading exclusion makes the mass of socially valuable transactions as high as it can be in steady state. Less intuitively, doing so also maximizes the average welfare of excluded agents in equilibrium conditional on the level of incentives provided by the threat of exclusion. We argue that these results are robust to a host of natural variations on our benchmark model. (JEL C73, D53, D86, G21, G32, G51)

Nonlinear Buckling of Fixed Functionally Graded Material Arches Under a Locally Uniformly Distributed Radial Load

Functionally graded material (FGM) arches may be subjected to a locally radial load and have different material distributions leading to different nonlinear in-plane buckling behavior. Little studies is presented about effects of the type of material distributions on the nonlinear in-plane buckling of FGM arches under a locally radial load in the literature insofar. This paper focuses on investigating the nonlinear in-plane buckling behavior of fixed FGM arches under a locally uniformly distributed radial load and incorporating effects of the type of material distributions. New theoretical solutions for the limit point buckling load and bifurcation buckling loads and nonlinear equilibrium path of the fixed FGM arches under a locally uniformly distributed radial load that are subjected to three different types of material distributions are derived. The comparisons between theoretical and ANSYS results indicate that the theoretical solutions are accurate. In addition, the critical modified geometric slendernesses of FGM arches related to the switches of buckling modes are also derived. It is found that the type of material distributions of the fixed FGM arches affects the limit point buckling loads and bifurcation buckling loads as well as the nonlinear equilibrium path significantly. It is also found that the limit point buckling load and bifurcation buckling load increase with an increase of the modified geometric slenderness, the localized parameter and the proportional coefficient of homogeneous ceramic layer as well as a decrease of the power-law index p of material distributions of the FGM arches.

Eigenproblem Versus the Load-Carrying Capacity of Hybrid Thin-Walled Columns with Open Cross-Sections in the Elastic Range

The phenomena that occur during compression of hybrid thin-walled columns with open cross-sections in the elastic range are discussed. Nonlinear buckling problems were solved within Koiter’s approximation theory. A multimodal approach was assumed to investigate an effect of symmetrical and anti-symmetrical buckling modes on the ultimate load-carrying capacity. Detailed simulations were carried out for freely supported columns with a C-section and a top-hat type section of medium lengths. The columns under analysis were made of two layers of isotropic materials characterized by various mechanical properties. The results attained were verified with the finite element method (FEM). The boundary conditions applied in the FEM allowed us to confirm the eigensolutions obtained within Koiter’s theory with very high accuracy. Nonlinear solutions comply within these two approaches for low and medium overloads. To trace the correctness of the solutions, the Riks algorithm, which allows for investigating unsteady paths, was used in the FEM. The results for the ultimate load-carrying capacity obtained within the FEM are higher than those attained with Koiter’s approximation method, but the leap takes place on the identical equilibrium path as the one determined from Koiter’s theory.

Analysis of Elasto-plastic Thin-shell Structures using Layered Plastic Modeling and Absolute Nodal Coordinate Formulation

A new elasto-plastic thin shell finite element of the absolute nodal coordinate formulation (ANCF) allowing for large deformation and finite rotation is proposed based on the Kirchhoff-Love theory and layered plastic model. The von Mises yield criterion of plane-stress with linear isotropic hardening is adopted in constitutive description of elasto-plastic material. Owing to the plane-stress constraint, special treatment should be given to the stress update algorithm for plasticity. To accommodate the plasticity formulation, the Gauss-point layered integration is inserted into the thickness of the element to produce the internal force. Then, the Jacobian of internal forces is deduced by deriving the consistent elasto-plastic tangent moduli. To accurately track the load-displacement equilibrium path in the buckling analysis of elasto-plastic thin shells, the arc-length method is used. The dynamics of the thin shells is also studied by using the generalized-alpha algorithm. Finally, several static and dynamic examples are presented to verify the accuracy of the proposed formulation.

Analytical Prediction for Nonlinear Buckling of Elastically Supported FG-GPLRC Arches under a Central Point Load

In this paper, we present an analytical prediction for nonlinear buckling of elastically supported functionally graded graphene platelet reinforced composite (FG-GPLRC) arches with asymmetrically distributed graphene platelets (GPLs). The effective material properties of the FG-GPLRC arch are formulated by the modified Halpin–Tsai micromechanical model. By using the principle of virtual work, analytical solutions are derived for the limit point buckling and bifurcation buckling of the FG-GPLRC arch subjected to a central point load (CPL). Subsequently, the buckling mode switching phenomenon of the FG-GPLRC arch is presented and discussed. We found that the buckling modes of the FG-GPLRC arch are governed by the GPL distribution pattern, rotational restraint stiffness, and arch geometry. In addition, the number of limit points in the nonlinear equilibrium path of the FG-GPLRC arch under a CPL can be determined according to the bounds of successive inflexion points. The effects of GPL distribution patterns, weight fractions, and geometric configurations on the nonlinear buckling behavior of elastically supported FG-GPLRC arches are also comprehensively discussed.

Large deformation behavior of functionally graded porous curved beams in thermal environment

The in-plane thermoelastic response of curved beams made of porous materials with different types of functionally graded (FG) porosity is studied in this research contribution. Nonlinear governing equations are derived based on the first-order shear deformation theory along with the nonlinear Green strains. The nonlinear governing equations are solved by the aid of the Rayleigh–Ritz method along with the Newton–Raphson method. The modified rule-of-mixture is employed to derive the material properties of imperfect FG porous curved beams. Comprehensive parametric studies are conducted to explore the effects of volume fraction and various dispersion patterns of porosities, temperature field, and arch geometry as well as boundary conditions on the nonlinear equilibrium path and stability behavior of the FG porous curved beams. Results reveal that dispersion and volume fraction of porosities have a significant effect on the thermal stability path, maximum stress, and bending moment at the crown of the curved beams. Moreover, the influence of porosity dispersion and structural geometry on the central radial and in-plane displacement of the curved beams is evaluated. Results show that various boundary conditions make a considerable difference in the central radial displacements of the curved beams with the same porosity dispersion. Due to the absence of similar results in the specialized literature, this paper is likely to provide pertinent results that are instrumental toward a reliable design of FG porous curved beams in thermal environment.

Convergence of Russian Regions: Different Patterns for Poor, Middle and Rich

The Strategy of Spatial Development of the Russian Federation until 2025 aims at the economic growth acceleration and reduction of the intra-regional socio-economic differences. Therefore, the factors affecting the economic growth of regions, convergence of regions, spillover effects from the neighbouring regions are of importance. Russian regions are very different and do not converge to a unique equilibrium path. 80 Russian regions were divided into the groups of poor, middle and rich regions. Three main hypotheses were considered, based on the differences in the 1) convergence speed, 2) influence of the same factors, 3) different mutual influence of regions. They were tested using a modified spatially autoregressive model for the three groups using the Russian regional data for 2000–2017. Beta-convergence was found only for the middle and rich regions, the rate of convergence was higher in the rich regions. The poor regions did not grow faster than the other regions, confirming the relevance of the Strategy of Spatial Development. The similarities and differences were identified in the factors ensuring the economic growth of regions belonging to the three groups. The growth in all regions is stimulated by the regional economy openness. The growth of rich regions can be achieved by increasing the investment and reducing the investment risk. However, the investments in the poor and middle regions are not effective. The poor and middle regions receive positive spillovers from the growth of the neighbouring regions. It is possible to expect reduced differences in the living standards between the poor and rich regions.

Impact of the structural model used on the steel hall fire resistance assessment

<p>It is presented in detail how the selection of a structural model describing steel hall frame in a more or less complex way may affect fire resistance evaluation for such hall. In the examples compiled in this paper the same typical one-aisle and single-story steel hall is subjected to simulated fire action, each time following the same fire development scenario. A resultant fire resistance is identified individually in each case, using various computational models, on an appropriate static equilibrium path obtained numerically. It is shown that the greater the simplification of the model used, the more overstated the estimated fire resistance is in relation to its real value. Such an overestimation seems to be dangerous to the user, as it gives him an illusory but formally unjustified sense of the guaranteed safety level.</p>

Domestic consumption and uncertainty of exchange rate in a Monetary union: Evidence from the Euro area

The research seeks to uncover how real consumption reacts to real exchange rate uncertainty in the short and long run for the world's largest monetary union the Euro zone. Twelve Euro zone countries were sampled covering the period 1995Q1-2019Q4. Using generalized autoregressive conditional heteroskedasticity (GARCH) and pooled mean group (PMG), the result shows that exchange rate uncertainty significantly dampens long-run consumption while the short-run effect is mixed. In the benchmark model, a negative and significant error correction coefficient was obtained, which allows to argue that i) there is evidence of a return to the long-run equilibrium path for consumption following short run deviations and ii) the speed of adjustment to equilibrium is low, with a coefficient of ~ 4%. This suggests that, in the Euro zone, convergence to long-run equilibrium is slow, as the proportion of disequilibrium corrected in one quarter, following a shock, is about 4%, which implies it would take ~17 quarters for one half of the disequilibrium, or deviations from the long-run consumption path to become corrected.