Impulse deformation of triangular plates based on the classical theory

This article discusses the impulse effects of various loads on triangular, isosceles, elastic, isotropic plates. Analytical solutions of the direct problem of determining the internal moments and deflections of the plate, as well as the numerical results of calculations of specific loading case are presented. Goal. The goal is to develop a method for solving direct problems of determining internal moments and deflections in rectangular triangular, isosceles, elastic, thin, isotropic plates. Methodology. To solve the direct problem, the Navier method, the classical theory of modeling vibrations of thin plates and the Laplace transform are used. Results. A technique has been obtained that allows one to obtain numerical and analytical dependences for calculating the internal moments and deflections in a triangular plate. Originality. For the first time, a technique was developed for solving direct non-stationary problems to determine the internal moments and deflections in rectangular triangular, isosceles, elastic, thin, isotropic plates based on the classical theory. Practical value. The obtained analytical dependences can be used to simulate impulse vibrations of square and isosceles rectangular triangular thin isotropic elastic plates, which can be critical structural elements.

Potential damage to residential building due to adjacent surcharge fill loading-case studies in Surabaya, Indonesia

Housing construction is a common construction activity and is always needed from time to time. House construction can be in the form of building new house or renovating an existing building. The impact of construction work to adjacent building or structure is something that cannot be avoided but must be minimized. The case study in this research aims to increase the awareness of all parties in construction project related to the potential damage to the surrounding buildings that may occur. This research was conducted with a case study on the construction of residential houses in Case A and Case B located in Surabaya-Indonesia. Field observations, analysis of damage causes, rectification methods and estimated cost were carried out in this study. These two case studies presented the damages analysis on residential house due to settlement which caused by adjacent surcharge fill loading. This settlement causes a differential settlement on both sides of the existing building, which had impacts on floor slope and cracks in wall. Proposed rectification works were made to restore the house to reach minimum serviceability requirement and prevent further damage in the future. The cost of repairing and retrofitting the damage existing house significantly increases the budget for a new house construction project. Therefore, careful planning in construction project considering the impact of soil settlement is needed more attention, especially in a dense urban area. Good communication and coordination between contractors and owners of neighbouring building are also needed to minimize the potential conflicts during or after construction works.

Control Oriented Maneuver Model of Prismatic Planing Hull

Roll yaw coupled dynamics are not well characterized and existing low cost models are limited in range of applicability. We utilize an interpolation based approach to address a wider range of conditions with reduced computational requirements. By interpolating test data to estimate hydrodynamic forces and empirically modeling roll damping and added mass, we establish a 4DOF maneuvering model for prismatic planing hulls in calm water. It is validated against relevant tests and show significant computational resource savings in comparison with potential flow based methods. Simulation of an extreme turning maneuver and an asymmetrical loading case demonstrates its potential for use in initial design, control and evaluation.

Development of a topology optimization method for the design of composite lattice ring structures

Composite lattice ring structures are known for their lightweight and high efficiency, which have a strong attraction in the aeronautical and aerospace industries. The general manufacturing process for such structures is to use wet filament winding technology. Due to the anisotropic properties of continuous fibers, the filament winding trajectory determines the mechanical properties of the composite lattice ring structures. In this work, a topology optimization method is proposed to generate the efficient filament winding trajectory, which follows the load transfer path of the composite part and can offer higher mechanical strengths. To satisfy the periodicity requirement of the structure, the design space is divided into a prescribed number of identical substructures during the topology optimization process. In order to verify the effectiveness and capability of the proposed approach, the topological design of ring structures with the different number of substructures, the ratio of outer to inner radius and the loading case is investigated. The results reflect that the optimal topology shape strongly depends on the substructure numbers, radius ratio and loading case. Moreover, the compliance of the optimized structures increases with the total number of substructures, while the structural efficiency of the optimized structures decreases with the radius ratio. Finally, taking the specified topological structure as the object, the conceptual design of a robotic filament winding system for manufacturing the composite lattice ring structure is presented. In particular, the forming tooling, integrated deposition system, winding trajectory and manufacturing process are carefully defined, which can provide valuable references for practical production in the future

Effect Of The Horizontal Component Of Earthquake On The Buckling Of Concrete Spherical Shells

The buckling failure of reinforced concrete spherical shell structures under the effect of the horizontal component of earthquake is investigated using a finite element method over a wide range of shell configurations. For this effect, two different loading case scenarios are considered; first, the shell is analyzed under the effects of the vertical seismic component alone. Then, the model is reanalyzed under the same loading conditions plus the horizontal earthquake component, taking into account two different horizontal-to-vertical earthquake spectral ratios. It is concluded that including the horizontal component of earthquake can result in a reduction in the buckling capacity of this type of structure; the impact of which is highly influenced by the horizontal-to-vertical earthquake spectral ratio and the shell geometry. It is also observed that the formulation adopted by ACI slightly overestimates the buckling capacity of spherical shells especially when horizontal seismic effects are included.

Effect Of The Horizontal Component Of Earthquake On The Buckling Of Concrete Spherical Shells

The buckling failure of reinforced concrete spherical shell structures under the effect of the horizontal component of earthquake is investigated using a finite element method over a wide range of shell configurations. For this effect, two different loading case scenarios are considered; first, the shell is analyzed under the effects of the vertical seismic component alone. Then, the model is reanalyzed under the same loading conditions plus the horizontal earthquake component, taking into account two different horizontal-to-vertical earthquake spectral ratios. It is concluded that including the horizontal component of earthquake can result in a reduction in the buckling capacity of this type of structure; the impact of which is highly influenced by the horizontal-to-vertical earthquake spectral ratio and the shell geometry. It is also observed that the formulation adopted by ACI slightly overestimates the buckling capacity of spherical shells especially when horizontal seismic effects are included.

Multidisciplinary design optimization of stamped and welded structures

Multidisciplinary design optimization (MDO) is very useful in present day engineering. The aim of this thesis is to develop and utilize an MDO procedure that can be applied to stamped and welded structures. This procedure involves new techniques such as material selection, weld constraint, and cost optimizations. The MDO is developed through five design iterations starting with a simple finite element model. As more techniques are added, the procedure progresses towards using a real life radiator support structure in a static loading case. Three trials were completed to optimize the cost of the structure; the final result is that the total cost was minimized by 20%. The MDO procedure was also applied to a real life wheel chair ramp model from a modified minivan. This structure was subject to a rear crash situation and the total mass, after the procedure was applied, was reduced by 19%.

Multidisciplinary design optimization of stamped and welded structures

Multidisciplinary design optimization (MDO) is very useful in present day engineering. The aim of this thesis is to develop and utilize an MDO procedure that can be applied to stamped and welded structures. This procedure involves new techniques such as material selection, weld constraint, and cost optimizations. The MDO is developed through five design iterations starting with a simple finite element model. As more techniques are added, the procedure progresses towards using a real life radiator support structure in a static loading case. Three trials were completed to optimize the cost of the structure; the final result is that the total cost was minimized by 20%. The MDO procedure was also applied to a real life wheel chair ramp model from a modified minivan. This structure was subject to a rear crash situation and the total mass, after the procedure was applied, was reduced by 19%.

Dynamic Simulation Analysis on Axle Spline of High-Speed Train Gauge-Change System

Spline couplings are widely used in transmission systems to transfer torque due to their higher load carrying capacity and better durability performance. Most researches are conducted under static and quasistatic loading cases; however, very little is known about their contact behavior and stress distribution under dynamic loading cases, especially as a key transmission component between wheel and axle. In this paper, a 3D dynamic contact and impact analysis model of the wheel-axle spline of high-speed train gauge-change system is employed in order to investigate the effect of driving velocity and assembling error and vibration on spline couplings. Three categories of loading cases are considered: (i) 0.3 m/s2 driving rate representing quasistatic loading case; (ii) 0.5 m/s2 driving rate representing normal loading case, and (iii) 1 m/s2 driving rate representing exceptional loading case. Aside from this, influence of spline misalignment, including radial misalignment and circumferential misalignment, has been investigated under normal loading case. Numerical results for surface integral contact analysis conducted by LS-DYNA and MATLAB were presented and compared for the verification of the results.

COMPARATIVE POWER CALCULATION OF THE LONGITUDINAL BEAM OF THE HEAD CAR BARROW IN THE SUBWAY ACTION IN THE MIDDLE OF THE BEAM OF UNIFORMALLY DISTRIBUTED LOAD

Priority directions and events among basic industries of municipal electric transport is resource saving in a transport system of underground passage during his exploitation. First of all this problem must be decided by scientific accompaniment, id est on the stage of planning of details and knots of transport vehicles. One of the basic tasks decided on the stage of planning is an increase of bearing strength of details due to the analysis of their tensely-deformed state. The article is sanctified to the calculation of supply of carrying capacity of stringer of front carriage of subway at operating under the middle of the equipartition loading case-insensitive transversal forces. Priority of research theme is reasonable, an aim and tasks are set forth. Two going offer near the power calculation of bearing strength of stringer: calculation on the assumed tensions and on the maximum states. The resilient models of beams are examined in both cases. In case of calculation on the maximum state mechanics of origin of plastic hinges is first of all grounded in the places of the hard fixing of ends of beam. A beam saves the bearing strength still. At the further height of the external loading appearance of plastic hinge is justified even in the middle of beam with a simultaneous loss by the beam of bearing strength. For the design of behavior of beam in accordance with her descriptions, including on tensions and by the condition of loss of her bearing strength. The mathematical raising of task of calculation of bearing strength of stringer at the calculation of possible tensions and maximum state is examined case-insensitive transversal force. Bearing strength of stringer is analysed at a calculation on possible tensions and on the maximum state. The analysis of the got results allows to judge about efficiency of an offer mathematical model on the whole. Got equalizations for the maximally possible loading at a calculation on the maximum states and on possible tensions allows reliably to estimate bearing strength of stringer in both cases. The increase of bearing strength of beam at a calculation on the maximum state is thrice-repeated. Drawn conclusion about adequacy of analysis of bearing strength of stringer.