Theoretical Analysis on Nonlinear Buckling, Post-buckling of Slender Beams and Bi-stable Mechanisms

Compliant Mechanisms (CMs) are used to transfer motion, force and energy, taking advantages of the elastic deforma- tion of the involved compliant members. A branch of spe- cial type of elastic phenomenon called (post) buckling has been widely considered in CMs: avoiding buckling for better payload-bearing capacity and utilizing post-buckling to pro- duce multi-stable states. This paper digs into the essence of beam's bucking and post-bucking behaviors where we start from the famous Euler–Bernoulli beam theory and then ex- tend the mentioned linear theory into geometrically nonlin- ear one to handle multi-mode buckling problems via intro- ducing the concept of bifurcation theory. Five representative beam buckling cases are studied in this paper, followed by detailed theoretical investigations of their post-buckling be- haviors where the multi-state property has been proved. We finally propose a novel type of bi-stable mechanisms termed as Pre-buckled Bi-stable Mechanisms (PBMs) that integrate the features of both rigid and compliant mechanisms. The theoretical insights of PBMs are presented in detail for future studies. To the best of our knowledge, this paper is the first ever study on the theoretical derivation of the kinematic models of PBMs, which could be an important contribution to this field.

Theoretical description of large deformations in criss-cross composites (with application to Tensylon®)

A theoretical model of an anisotropic material, Tensylon®, under large strains is proposed. This model is capable to describe the material’s response in in-plane tension at different angles to the fibrils. At 0° and at 90°, i.e., along the fibrils in either “criss” or “cross” plies, it quantitatively predicts the experimentally observed elastic behaviour until failure. At 45° to the fibrils, it quantitatively describes the experi- mental data in the elastic and plastic domains. The description remains accurate up to strains of 35%, that corresponds to 30÷40% of deforma- tion gradient components. The infinitesimal strains model would give at least 25% of error under such circumstances.

NONLINEAR MODEL OF DEFORMA TION OF COMPRESSIBLE SOILS

The possibility to apply a physically and geometrically non-linear model of a hyperelastic isotropic material to the description of strains of non-rocky soils is considered. The study examines the stability of the model, restrictions on the model constants, and the definition of the range of deformations within which the model is Drucker stable.

MAN-CITIZEN-INTELLECTUAL IN THE INTERPRETATION OF UKRAINIAN AND POLISH EMIGRATION ON THE PAGES OF “CULTURE” BY J. GIEDROYC

The article is devoted to the elucidation of the points of view, considerations and discussions of Ukrainian and Polish emigrants from the circles united around the Parisian magazine “Culture” by J. Giedroyc on the deformation of a human-intellect- citizen in the Soviet totalitarian society. Immediately after its foundation, the well-known Polish emigration magazine “Culture” designated his pages as a place for the intellectual meetings of the authors describing the essence of Soviet totalitarianism, the importance of exposing illusions about the absence of the threat of sovietism to the countries of Western Europe, realizing that com- munism is in the same degree dangerous for European culture, as there was dangerous German Nazism before. First of all Polish and later Ukrainian intellectuals (writers, historians, publicists, journalists) focused their attention on reflections on the deforma- tion of the human-intellectualist-citizen in the totalitarian world. Articles by J. Ławrinenko, Julian Kardosz (E. Małaniuk), J. Sze- rech-Szewelow, Cz. Miłosz, G. Herling-Grudziński, J. Czapski and many other dissidents living in Western democracies, hold the necessary distance to look carefully at the methods of the Soviet repressive system and the effects of total propaganda. The research material consists of the texts of these authors from the post-war decade. Despite the fact that this is a relatively short moment in the decades-long dominance of the Soviet regime in a large part of European territories, even it reveals the scale of crimes committed against a man forced to live in the Soviet regime in the countries behind the Iron Curtain. Published in “Culture” texts belonging to various literary and non-literary genres show us the essence of totalitarianism existing in the homelands of their authors – it is total power over every citizen, manifesting from physical destruction (unjustified arrests, abductions, exiles to camps, shootings) to the spiritual humiliation by torture with the atmosphere of fear, terror, informing, uncertainty, indoctrination. The level of merciless means of maintaining this total power in Poland was somewhat weaker in comparison to Ukraine, but at the same time did not change its basic striving to suppress and eliminate any individual or collective opposition of the communist ideology. That is why it is particularly important to consider points of view, meditation and discussion of the Polish and Ukrainian perspectives on Soviet totalitarianism, its ideology, which has entered all aspects of human existence.

The features of the Paleozoic-Mesozoic complexes of Kiber Cape (Chukotka, Arctic Russia): a structural-deforma-tion analysis

Three major regional deformation stages of Central Chukotka tectonic evolution were determined in Paleozoic-Mesozoic deposits of Kiber Cape. The research was based on a structural analysis of the linear and planar elements. Ellesmerian (Late Devonian) structural parageneses were masked during (at least) two phases of young Mesozoic-Cenozoic deformations: syncollisional North-North-East - South-South-West and North-West - South-East regional compressions and post-collisional extension of various directions, followed the compressions. The structural data comparison was made for Kiber Cape region, South-Anyui suture and Western Chukotka sector. It was emphasized that these regional units have similar structure styles and coeval phases of the tectonic transformations.

Hot Forming Process Analysis of Ti6Al-4V Alloy: Experiment, Behaviour Modelling and Finite Element Simulation

The present investigation aims at evaluating and understanding the thermo-mechanical be-haviour of a titanium alloy under hot forming conditions. In this work, several considerations are ad-dressed. First, Scanning Electron Microscopy observations are performed to assess the evolutions of(α − β) phases, grain size, defects regarding the thermo-mechanical loadings from different static anddynamic tests (various temperatures and strain rates). Hence, the relationships between mechanicalproperties and micro-structure evolutions in such conditions allow a first assessment of the deforma-tion mechanisms in link with the macroscopic stress-strain curves. Afterwards, a behaviour modelformulation associated to an identification procedure of the parameters of the constitutive equationsis proposed. Finally, several tests performed under hot forming conditions and conducted on an in-dustrial press are compared to Finite Element calculations. Results are compared and provide someinteresting improvement ways in order to investigate the influence of the process parameters on thefinal shape of the part.

THE MĒSU-TREE AND THE ANIMAL INSIDE: THEOMORPHISM AND THERIOMORPHISM IN DANIEL 4

The present article offers an analysis of Daniel 4. It argues that the literary origins of the tree imagery in the biblical text most probably lie in Mesopotamian conceptions of the mēsu-tree, the tree that supplies the flesh of the gods, the material of their statuary presence. The presence of the imagery in Ezekiel 31 suggests that the Mesopotamian concept was incorporated into exilic and post-exilic redefinitions of the legitimate channels of the iconic worship of YHWH. Within a priestly redefinition of YHWH's iconic presence in Judah, Adam's physical resemblance to YHWH provided in humanity the only legitimate alternative to idol worship. Daniel 4 and its context exhibit similar ideological concerns and construct a similar solution to the ongoing iconic dilemma: humanity functions as the only legitimate equivalent of ancient Near Eastern cultic statues, as the replacement of YHWH's cultic statue of the First Temple no longer extant. The iconic connotation of the tree imagery requires a reassessment of the animal deforma¬tion of the tree, albeit a late addition to the original stratum of the narrative. Commonly interpreted through the lens of ancient Near Eastern depictions of human heroes with animal traits or life-habits, Nebuchadnezzar's loss of his dendromorphism can only mean in the terms of the parable the deformation of a theomorphic state. Within the parameters of this ideological context and of the tree parable, by losing his theomorphism and becoming theriomorphic, Nebuchadnezzar ceases to be object of worship and becomes worshipper. Moreover, in his deformation he also destroys the only legitimate object of iconic worship: himself. The context of Daniel 4, namely Daniel 3 and Daniel 5, suggests that in its deformed state humanity is only left to mistakenly worship idols.

Influence of Geometry and Deformation on the Performance of Profiled Hydrosatic Thrust Bearings

In a previous study, the authors investigated the effect of various thrust bearing profiles on the bearing performance and concluded that bearing performance is significantly influenced by the deformations resulting from lubrication film pressure. In the present work, results from a recent study on the effect of the interaction between the ball-joint and bearing on bearing deforma tion and hence, on bearing performance are reported. The motivation behind the study is to investigate the impact of raising or lowering the contact area between the ball-joint and bearing surface on bearing performance as this has the effect of influenceing the bearing deformation. Several designs involving various geometries of the bearing that affect the contact area are considered. The coupled fluid-solids problem is solved by using an iterative technique where the fluid problem is solved using the lubrication theory and the bearing deformation is analyzed by using the commercial FEA software ABAQUS standard. Results from the numerical simulations are compared with experimental results for the standard design of the bearing. The effect of varying the pocket width on the load carrying capacity of the bearing is also investigated.