Impact of mechanical vibrations introduced by up blasting on the structure and hardness of welds on P235GH steel during MAG welding process

This article discusses the effects of surfacing with the introduction of mechanical vibrations into the material using shot blasting. It does not require a rigid attachment of the vibrating system to the base material, and vibrations are introduced as a result of supplying energy of collision of the shot with the parent material. The effect of introducing mechanical vibrations through shot blasting during welding of P235GH steel on the structure and hardness of obtained structures was described. Comparative results of tests revealing the basic differences in the structural structure and hardness of reached welds without shot blasting and with its participation were presented. As a result of the conducted research, differences in the structural structure of the welds were shown and it was shown that shot blasting is an effective and alternative method of introducing mechanical vibrations supporting welding processes.

The Trouble is Politics

This concluding chapter argues that Thailand is suffering from a surfeit of legalism: revolving-door constitutions, politicized independent agencies—including a problematic Constitutional Court—and a judiciary that works on behalf of an imagined monarchy, rather than in the public interest. The results are plain to see: a profound degree of political instability, high levels of social polarization, very high conviction rates, the abuse of punitive treason spectrum laws, and a prison population that is rising uncontrollably. Far from easing tensions through reflexive and moderating decisions, the courts have aggravated matters and fueled growing levels of crisis. Courts should strive for “tribunality”: the pragmatic and judicious resolution of complex political problems. Trials should also provide for moments of “liminality,” when the use of legal ritual and formality creates episodes of catharsis. A judiciously conducted trial can move conflict into the realm of ritual, moderating disagreements and producing a solution that captures nuance and maintains ambiguity. Such liminality prepares the way for tribunality: practical judicial solutions that are grounded in political and social realities rather than in rigid attachment to the letter of very imperfect laws. However, the more Thai judges see themselves as enforcing loyalty to the crown, the more unattainable even brief glimpses of tribunality and liminality become.

Determination of the frequencies and forms of free vibrations of pentagonal plates by the finite-element method

Frequencies and modes of free vibrations of an isotropic thin pentagonal plate of regular shape with various configurations of rigid attachment at the edges are determined using the finite element method (FEM). The results obtained for some pentagonal plates are compared with the results obtained for square plates of an equivalent mass with corresponding boundary conditions. We present the vibration modes of the studied plates and the topology of the vibration modes for some of the considered plates corresponding to the square plates with free edges and rigidly fixed edges. The reliability of the obtained results is ensured by the use of a substantiated mathematical model, the correct formulation of the problem and the practical convergence of the calculated frequencies when using the FEM.

Validation of a Newly Proposed 3D Flexible Ring Tire Model Through Adams FTire Full-Vehicle Simulations

Flexible ring tire models are widely used for vehicle durability and ride comfort analysis. In our previous research, a novel 3D flexible ring tire model was proposed, and the model’s parameter identification and predictability were illustrated based on various tire cleat tests. To further demonstrate its capability, this paper applies the tire model in a full-vehicle model for various full vehicle bump tests with different driving speeds and cleat orientations in Matlab programing. The tire model and the full-vehicle model are connected through a suspension system, with the suspension spring and damper along the vertical direction, and rigid attachment along the longitudinal and lateral directions. The predicted results are compared against ADAMS® full-vehicle FTire virtual tests with the same simulation conditions. The comparison variables include tire forces, vertical displacements, and suspension jounce movements. The results provide useful guidance for the design of vehicle suspension.

Research of influence of constructive solutions to the nodes of metal structures under random design

This article presents a problem of researching of the intense deformed state of units of metal structures for the purpose of optimization this units in the case of the variant design of buildings and structures with a metal frame. There are examples of results which were get after laboratory experiment and computer modeling the same unit. The laboratory experiment was made on a optically-sensitive model, in other words, by photo elasticity method, which visualizes the difference of the main tension. And the same picture was get after the ANSYS computer model was designed. It is noted that in the traditional approach the designer develops a limited number of options, the consideration of which does not guarantee the closeness of the final result to the optimum. The authors indicate that the problem of development of new or improvement of existing methods of optimization of design decisions of structures is relevant, and its solution is one of directions of perfection of computer-aided design, which require verification of accuracy. One way to test the accuracy of a polarization-optical method, which is based on the property of most of the isotropic transparent material to acquire under the action of mechanical stresses (deformations) the ability to double refraction (optical anisotropy). In the study of spatial computer models developed in ANSYS, the authors obtained isopole of the principal stress distribution in the analyzed section of the model. The analysis of the received results of researches of stress state of the rigid attachment of the farm to the column, the experimental method of photoelastic analysis and obtained on a computer model in ANSYS revealed a clear convergence of the results.

Models of Aqueducts with Different Height-Width Ratio on Rigid Buttress

Modified Housner model is presented in the paper for seismic analysis of aqueducts on rigid buttress. Invective mass is attached to walls of aqueducts rigidly instead of springs with low stiffness, which ensures vibrating frequencies can be computed. The coefficient α of invective mass is introduced to adjust the enlargement brought by the rigid attachment. The value of the efficient for aqueducts with different height-width ratio is determined by tentative calculation. Modified Housner model inherits the merit and avoids shortcoming of conventional Housner model. Finally the modified model is verified by an example and the accuracy of the model is proved to meet requirement of practical seismic analysis.

Design and Testing of Tie-Down Systems for Temporary Barriers

Two tie-down temporary barrier systems were developed and crash tested according to the safety performance criteria provided in NCHRP Report 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features. Both tie-down systems were designed to reduce barrier displacements and to retain deflected barriers on the bridge deck edge. The first system consisted of a steel tie-down strap concept for use with the Iowa F-shape temporary concrete barrier. At each barrier joint, the trapezoidal-shaped strap retained the vertical pin and was attached to the concrete bridge deck using two drop-in anchors. An acceptable fullscale vehicle crash test of the tie-down strap concept was conducted according to the Test Level 3 (TL-3) impact safety standards in NCHRP Report 350. The second tie-down system was developed for use with Iowa’s steel H-section temporary barrier. A new barrier connection was developed to simplify barrier attachment and to accommodate deviations in horizontal and vertical alignment. It consisted of two steel shear plates positioned within an opening on the adjacent barrier section and held in place with two steel drop pins. Four steel angle brackets were welded to the barrier’s base to allow for rigid attachment to the concrete bridge deck with drop-in anchors. Two full-scale vehicle crash tests were conducted on the steel H-barrier system according to TL-3 impact safety standards found in NCHRP Report 350. After an unacceptable first test, the system was successfully tested with minor design modifications.

A Boundary Integral Analysis of Lugs Attached to Cylindrical Pressure Vessels

Integral equations are derived to calculate the stresses and displacements in the neighborhood of a load-carrying rigid attachment in a shallow cylindrical shell. The integral equation formulation is simplified by modifying existing Green functions for the unbounded shell to account for simply supported boundary conditions at the ends of the vessel. The resulting equations are solved numerically. Three forces and three moments applied to the attachment are the loadings considered. Results for circular attachments agree with those found by other authors using different solution methods and with experiments.