Shareholder Collaboration

Two models of the firm dominate corporate law. Under the management-power model, decision-making power rests primarily with corporate insiders (officers and directors). The competing shareholder-power model defends increased shareholder power to limit managerial authority. Both models view insiders and shareholders as engaged in a competitive struggle for corporate power in which corporate law functions to promote operational efficiency while limiting managerial agency costs. As scholars and judges continue to debate the appropriate balance of power between shareholders and insiders, corporate practice has moved on. Increasingly, the insider–shareholder dynamic is collaborative, not competitive. This Article traces the development of insider–shareholder collaboration, explaining how collaboration, which originated in the venture capital context, has expanded into public companies. This expansion, the Article argues, is due to the increasing importance of partial information problems that, for many firms, have grown costlier than agency costs. Using insights from the economics of information, the Article shows how collaboration promotes the production and aggregation of information from insiders and shareholders, adding value that is lost under unilateral decision-making. Modern corporate law and corporate governance are poorly prepared to handle insider–shareholder collaboration, however. The collaborative process places novel demands on traditional obligations of confidentiality and fiduciary duty as well as complicating the meaning of conflicts of interest. These concepts must be rethought to enable productive collaboration while limiting the potential that the collaborative process can be manipulated to permit collusive behavior or self-dealing

3D strip model for continuous roll-forming process simulation

Abstract The paper addresses the complexities for a reliable numerical simulation of the roll forming process. During the process, the material is progressively bent accumulating plastic deformation at each forming step. Strain hardening limits the material formability and may causes flaws of the final shape. A simplified method for the FEM modeling of the process has been developed introducing a narrow-strip 3D model. This approach leads better performance than the classical modeling method, in terms of results reliability and low computational time. In order to verify the proposed model, an experimental campaign of testing, for a specific roll forming production process, was carried out. On the quasi-static regime, the post necking behavior of the sheet metal was characterized. The Vickers hardness and the plastic strain of uniaxial tests were empirically correlated. By the hardness correlation, the plastic strain accumulated at different stages of the process was evaluated and compared with the numerical results. Further possible improvements of the method are highlighted

Numerical FEM Evaluation for the Structural Behaviour of a Hybrid (bonded/bolted) Single-lap Composite Joint

Abstract The structural behaviour of a single-lap hybrid (bonded/bolted) composite joint subjected to a tensile external load was evaluated by means of the Finite Element Method (FEM). In particular, the distribution of stresses acting in its adhesive layer was compared with that relative to the case of a simply adhesive bonded joint. Furthermore, the load transferred by the bolt was determined at different characteristics of the adhesive and of the applied external tensile load, corresponding to both single and double bolt configuration. The obtained values were in turn compared with experimental data found in literature, so validating the produced numerical simulations

Mechanical behavior of chemically-treated hemp fibers reinforced composites subjected to moisture absorption

Natural Fibers Reinforced Composites (NFRC) are finding much interest as substitutes for glass- or carbon-reinforced composites thanks to their lightness, easy handling, processing and recyclability. However, their polarity makes them incompatible with hydrophobic thermoplastic matrices, leading to extended moisture adsorption which causes the debonding between fibers and matrix, affecting, thus, the mechanical properties of NFRCs. In the present work, NFRCs were manufactured using hemp fibers previously chemically treated with NaOH alkali solutions or (3-Glycidyloxypropyl) trimethoxysilane (GPTMS) solutions of various concentrations. To assess the effectiveness of the used chemical treatments in hindering the moisture adsorption and the entailed mechanical failure of the NFRCs, untreated and treated hemp fibers based composites were subjected to moisture adsorption test and then to tensile testing as a function of the chemical treatment, temperature and concentration of reagents. The results show that the treatments with 5 wt% of both NaOH and GPTMS are the most effective, reducing composites' water uptake from 7.74% to 6.46% and 5.58% respectively at room temperature, and from 9.67% to 8.19% and 8.13% respectively at 50 °C. Moreover, the comparison between the mechanical testing results carried out before and after the moisture adsorption test, shows that the water uptake induces mainly a stiffness decrease (about 50% when alkali treatments were used and about 60% using silane treatment), while not significantly affect the loading capability of the composites regardless of chemical treatment. However, the specimen obtained using 5 wt% GPTMS is more effective in the prevent the failure of the composite induced by water uptake

Fatigue behavior of hybrid and bonded single lap joints made of composite material

Joining of composite materials can be performed with different techniques and, in particular, trough mechanical fasteners, bonding, hybrid solutions. In last years, hybrid (bolted/bonded) joints are attracting the interest of several companies and scientific community, since the use of both techniques permit to overcome some critical aspects connected to the separate usage of adhesive and bolts, i.e., negative effects of the environmental conditions on adhesive, localized stresses at the notch. This paper aims to improve the knowledge about the fatigue behavior of hybrid CFRP (Carbon Fiber Reinforced Polymer) joints. For the purpose, experimental fatigue and static tests are performed on hybrid and bonded joints and the results herein discussed. Results are post-processed with the main goal to highlight the benefits led to the hybrid technique with respect to the bonding one

Neural networks for fatigue crack propagation predictions in real-time under uncertainty

Crack propagation analyses are fundamental for all mechanical structures for which safety must be guaranteed, e. g. as for the aviation and aerospace fields. The estimation of life for structures in presence of defects is a process inevitably affected by numerous and unavoidable uncertainty and variability sources, whose effects need to be quantified to avoid unexpected failures or excessive conservativism. In this work, residual fatigue life prediction models have been created through neural networks for the purpose of performing probabilistic life predictions of damaged structures in real-time and under stochastically varying input parameters. In detail, five different neural network architectures have been compared in terms of accuracy, computational runtimes and minimum number of samples needed for training, so to determine the ideal architecture with the strongest generalization power. The networks have been trained, validated and tested by using the fatigue life predictions computed by means of simulations developed with FEM and Monte Carlo methods. A real-world case study has been presented to show how the proposed approach can deliver accurate life predictions even when input data are uncertain and highly variable. Results demonstrated that the “H1-L1” neural network has been the best model, achieving an accuracy (Mean Square Error) of 4.8e-7 on the test dataset, and the best and the most stable results when decreasing the amount of data. Additionally, since requiring only very few parameters, its potential applicability for Structural Health Monitoring purposes in small cost-effective GPU devices resulted to be attractive

Correlation between real geometry and tensile mechanical behaviour for Ti6Al4V electron beam melted thin specimens

The Electron Beam Melting (EBM) is an Additive Layer Manufacturing (ALM) technique used to directly manufacture 3D functional parts from metal powder, selectively melted, layer by layer, by an electron beam according to a geometry defined by a CAD model. The EBM technology allows benefitting from countless advantages: material waste reduction, easy manufacturing of complex shapes, lead time reduction, etc; on the other hand the EBM process is typically associated with lower resolutions and higher surface roughness (Ra = 25–30 μm) compared to similar laser based powder bed metal processes. Therefore the surface morphology may be a critical issue for the structural integrity of components made in EBM and used in-service in their “as built” condition, i.e. with the characteristic surface released by the process. This study evaluates surface morphology and tensile properties of Ti6Al4V specimens of varying nominal thickness (1–5.0 mm), made by using EBM process with a layer thickness of 50 μm. The aim is therefore to investigate how the surface morphology and the tensile properties are affected by the nominal thickness of the component

Established Numerical Techniques for the Structural Analysis of a Regional Aircraft Landing Gear

Usually during the design of landing gear, simplified Finite Element (FE) models, based on one-dimensional finite elements (stick model), are used to investigate the in-service reaction forces involving each subcomponent. After that, the design of such subcomponent is carried out through detailed Global/Local FE analyses where, once at time, each component, modelled with three-dimensional finite elements, is assembled into a one-dimensional finite elements based FE model, representing the whole landing gear under the investigated loading conditions. Moreover, the landing gears are usually investigated also under a kinematic point of view, through the multibody (MB) methods, which allow achieving the reaction forces involving each subcomponent in a very short time. However, simplified stick (FE) and MB models introduce several approximations, providing results far from the real behaviour of the landing gear. Therefore, the first goal of this paper consists of assessing the effectiveness of such approaches against a 3D full-FE model. Three numerical models of the main landing gear of a regional airliner have been developed, according to MB, "stick," and 3D full-FE methods, respectively. The former has been developed by means of ADAMS® software, the other two by means of NASTRAN® software. Once this assessment phase has been carried out, also the Global/Local technique has verified with regard to the results achieved by the 3D full-FE model. Finally, the dynamic behaviour of the landing gear has been investigated both numerically and experimentally. In particular, Magnaghi Aeronautica S.p.A. Company performed the experimental test, consisting of a drop test according to EASA CS 25 regulations. Concerning the 3D full-FE investigation, the analysis has been simulated by means of Ls-Dyna® software. A good level of accuracy has been achieved by all the developed numerical methods

Capillary barriers during rainfall events in pyroclastic deposits of the vesuvian area

In the present paper, the capillary barrier formation at the interface between soil layers, which is characterized by textural discontinuities, has been analyzed. This mechanism has been investigated by means of a finite element model of a two-layer soil stratification. The two considered formations, belonging to the pyroclastic succession of the “Pomici di Base” Plinian eruption (22 ka, Santacroce et al., 2008) of the Somma–Vesuvius volcano, are affected by shallow instability phenomena likely caused by progressive saturation during the rainfall events. This mechanism could be compatible with the formation of capillary barriers at the interface between layers of different grain size distributions during infiltration. One-dimensional infiltration into the stratified soil was parametrically simulated considering rainfall events of increasing intensity and duration. The variations in the suction and degree of saturation over time allowed for the evaluation of stability variations in the layers, which were assumed as part of stratified unsaturated infinite slopes