A metal sheet stiffened by a partially debonded composite quarter-plate

An isotropic sheet stiffened by means of an orthotropic quarter-plate is considered. The quarter-plate is assumed to be perfectly bonded to the metal sheet everywhere except an area of debonding which may develop due to high stress concentrations. The adhesive which has a small constant thickness is treated as a shear spring. The loads are applied at infinity and supposed to be transmitted through the metal plate. Shear stress distribution between the two plates was obtained from the continuity of displacements along an area where they were bonded to each other

Several intact or broken stringers attached to an orthotropic sheet with a crack

Several intact or broken stringers which are continuously attached to a cracked orthotropic sheet through an adhesive are considered. The effect of orthotropy on the stress intensity factors is investigated. The stringers are assumed to be partially debonded due to high stress concentrations. The shear stress distribution between the stringers and the plate and the stress intensity factors are obtained from an integral equation which represents the continuity of displacements along the bond lines

A note on a broken layer in an orthotropic laminate composite

An orthotropic laminate composite containing a completely broken layer is considered. The problem is formulated in terms of integral transforms and then reduced to a singular integral equation which is solved numerically. The strength of stress singularity at the crack tip is determined from a characteristic equation which is obtained by studying the dominant part of the singular integral equation near the end points. The stress intensity factors are given for various material properties

The stress distribution in tempered glass due to a crack

A model describing the failure in tempered glass is proposed and a method of solution is presented. An infinite elastic strip is assumed to represent the glass and the loads vanish everywhere on the boundary as well as at infinity. The problem is solved using the integral equations technique where the input is the residual stresses in the glass

Fracture and contact problems for an elastic wedge

The plane elastostatic contact problem for an infinite elastic wedge of arbitrary angle is discussed. The medium is loaded through a frictionless rigid wedge of a given symmetric profile. Using the Mellin transform formulation the mixed boundary value problem is reduced to a singular integral equation with the contact stress as the unknown function. With the application of the results to the fracture of the medium in mind, the main emphasis in the study has been on the investigation of the singular nature of the stress state around the apex of the wedge and on the determination of the contact pressure

Fiscal Policy and Economic Activity: U.S. Evidence

We investigate the dynamic effects of five different fiscal shocks on the US economy using a structural vector autoregressive (SVAR) model that uses Blanchard-Quah type restrictions. We find that an increase in indirect taxes or in corporate taxes has a contractionary effect on the economy, while an increase in personal taxes is neither contractionary, nor expansionary. These results imply that the Ricardian Equivalence hypothesis holds only for personal taxes. On the spending side, we find that an increase in government wages and salaries has a contractionary effect on the economy, while an increase in defense spending is expansionary. Our results suggest that different fiscal shocks have different and offsetting effects on the economy, and using aggregated data may, therefore, conceal the effects of fiscal policy.

International Transmission of Fiscal Shocks: An Empirical Investigation

This paper investigates how innovations in income taxes and government purchases originating in the U.S. affect the U.S. economy, and how these effects are transmitted to the Canadian economy. Using a semi-structural VAR model and data for both countries for the 1961:1-2004:3 period, we find that fiscal policy innovations originating in the U.S. are transmitted to the Canadian economy by international trade and capital flows through interest rate and exchange rate channels. Unanticipated shocks to U.S. government purchases have beggar thy neighbor effects on Canada. U.S. output increases and Canadian output decreases in response to a positive shock to U.S. government purchases. In response to an unanticipated increase in U.S. income taxes, U.S. output declines while U.S. and Canadian real interest rates rise. The response of Canadian output, however, is not significantly different from zero.

Oil Wealth and Economic Growth Revisited: A Bayesian Model Averaging Approach

We investigate the effect of oil revenues on long-term economic growth within a Bayesian framework that accounts for model uncertainty. Our anal- ysis is based on an updated cross country data set for long term growth in the period 1970-2014 including 91 countries and 54 potential growth deter- minants. Initially, we do not find any empirical evidence for the existence of the \natural resource curse in our sample. On the contrary, we document a robust positive effect of oil rents on long-term economic growth. Then, we introduce interaction terms of oil rents with potential conditions under which oil dependency can lead to sub-standard growth. Our second set of results shows that the interaction of institutional quality and oil revenues has a ro- bust positive effect on growth, while the constituent oil rent term is no longer robust. We conclude that institutional quality is necessary condition for oil revenues to have a growth-enhancing effect

A cracked sheet stiffened by several partially debonded intact or broken stringers

The effect of several stringers on the stress intensity factors at the tips of a crack is considered. The stringers which were continuously attached to the plate and placed perpendicular to the crack may be partially debonded due to high stress concentrations. Since the stringers may even break under excessive loading conditions, both intact and broken stringers are considered to investigate the effect of rupture. The continuity of displacements along the bond lines leads to an integral equation which is solved to give the shear stress distribution in the adhesive and the stress intensity factors at the crack tips

An orthotropic laminate composite containing a layer with a crack

A laminate composite containing an orthotropic layer with a crack situated normal to the interfaces, and bonded to two orthotropic half-planes of dissimilar materials was considered. The solutions for two different classes of orthotropic materials are presented. In each case, the problem was first reduced to a system of dual integral equations, then to a singular integral equation which was subsequently solved numerically for the stress intensity factors at the tip of the crack. The effect of the material properties on the stress intensity factor was investigated. The generalized plane stress and the plane strain were treated simultaneously