Wieslaw Krason

Simulations of motion of prototype railway wagon with rotatable loading floor carried out in MSC Adams software

The railway wagon with a low flat rotatable loading floor was analysed in the paper. Such a structure can be used for transporting various types of vehicles such as tractors, trucks, trailers, semitrailers, cargo containers. The railway wagon allows quick and fast loading and unloading without any platform infrastructure or terminals. Only a hardened flat surface is required. Each railway wagon can be loaded-unloaded individually (no cranes needed). This construction has a wide range of application and is easy to operate. The model of a railway wagon consisted of standard carriages, undercarriages, and a rotatable loading floor was developed. The model was built of rigid solids. Between individual elements of the model, the appropriate joints and contact connections were created. The model was analysed using MSC Adams code, which allows performance of the 3D kinematic – dynamic analyses of the entire model. The analyses were carried out with use of the model of the loaded semitrailer. Passage of the railway wagon with a trailer on horizontal rails, which are the smallest standard arc with a radius 250m, was simulated at different speed. Reactions occurring in couplings of the rotatable loading floor, which are the main element of connection between the rotatable loading floor and motionless undercarriages part of the frame of the wagon, were tested. The maximum velocity at which the railway wagon can move was analysed as well. There was also examined the speed at which the wheels separate from the rails, what results in derailment of the whole wagon.

Experimental investigations of double multi - leaf spring subjected to impact load

The article deals with experimental investigations of a prototype double multi-leaf spring, compound of a fourleaf main spring and a double-leaf supporting spring subjected to an impact test. In real conditions of car movement (e.g. curb, bump), dynamic oscillating loads, which generate dynamic stress in a car suspension affecting other elements of the car, occur. Consequently, effects of coupled oscillations having a great impact on comfort of a driver and passengers can be observed. The research was conducted in the Laboratory of Material and Construction Strength Department of Mechanics and Applied Computer Science (DMACS) in the Faculty of Mechanical Engineering of Military University of Technology. The experiment was carried out on an original construction of a spring impact hammer developed in DMACS. Energy of the impact was set up by changing mass of a beam with beater and beam dropping height. The results were presented in the form of table summaries, time-dependent load and displacement graphs. The methodology of the research presented in the paper and a set of measuring equipment can be utilized to evaluate load and vibrations of any multi-leaf spring under impact load with given energy. The experimental results obtained from the test are supposed to be used to verify and develop FEM model describing a spring under impact load and oscillations.

Selected aspects of simulation of multi - module mechanisms with the use of multibody method

The paper presents numerical analysis of a single segment of a floating bridge built in the form of a metal cassette with a movable bottom. An internal elastic container – a pontoon filled with the air was fixed in the cassette [4]. It enables a fluent change of displacement of a single segment and of a floating ribbon assembled from segments. A multibody analysis of cooperation of the cassette in the process of filling the pontoon and opening the cassette was discussed. Numerical analysis of a single cassette presented in the paper constitutes a part of tests including stand tests. The single floating cassette has a typical shelled construction consists of a tight deck, a pneumatic chamber closed with a reinforced movable bottom and sets of fastenings together with a mechanism of bottom opening. Each cassette is equipped with a highly resistant elastic or semi-elastic cushion hereinafter called a pontoon. The movement of the bottom and the process of opening the cassette module with a pneumatic air cushion realized under an influence of pressure of the compressed air. As a result of uneven filling the individual chamber of the pontoon with the air or their uneven emptying in the process of closing the cassette, there can occur the asymmetry of displacements of the bottom resulted even in seizing of telescopic mechanisms. In the paper were considered the cases of symmetrical and asymmetrical movement of the bottom corresponding to symmetrical and unsymmetrical pull out of the telescopic mechanism modules. Dynamical analysis of movement of cooperating subsystems of the floating cassette was carried out with the use of MSC.Adams code [5, 8].

Multi - body simulations of railway wagon dynamics

The main aim of the presented paper is to verify the dynamics of chosen railway wagon using multi-body methods. Thus, in tests a wagon prototype with rotational rail-car body was simulated, which is going to be used for TIR vehicles trailer bodies transporting. Implemented prototype is authored by the team from Department of Applied Mechanics and Computer Science from Faculty of Mechanical Engineering in Military University of Technology. For this purpose CAD model, and subsequently numerical model, of mentioned wagon was developed. Using MSC Adams software initial boundary conditions, material parameters and contact characteristics were defined. In the previous authors’ paper [1], preliminary analyses of the loads acting on the railway platform were carried out, which verified chosen parameters and coefficients. The main aim of presently proposed 3D multi-body simulations of railway wagon is to investigate its motion with full load and to determine the operation limit safety. Thus, in the performed analyses the railway wagon was accelerated to the desired velocity and drove through the curved tracks with four different velocities. From the carried out simulations the wagon dynamic behaviour was investigated and obtained results including contact forces characteristics were compared from all analyses cases. Moreover, performed study shows that the MSC. Adams software is capable for analysing and simultaneously validating various complex engineering problems, such as the one investigated by the authors

Strength testing of side connector of railway wagon for semitrailers transport

A prototype railway wagon with a rotatable platform for an intermodal system is developed in Military University of Technology. The special railway wagon is equipped with a rotatable low flat loading floor. It can be used for transporting various types of vehicles, for example, tractors, trucks, trailers, semitrailers, cargo containers. The special wagons allows quick and convenient self-loading and unloading of vehicles and containers (no cranes needed); no platform infrastructure is required, only hardened flat surface; there is no need for hubs, terminals or special logistics; each wagon can be operated separately. A considered wagon consists of the following elements: chassis with biaxial standard Y25 bogies, frame, platform body, pneumatic systems, buffer devices, other external devices, electric equipment and hydraulic systems. A mechanism blocking rotation of a rotatable platform during transport of the load (typical semitrailers) is very important from a functionality and strength point of view of the considered wagon. Construction of such a lock allows only transmission of longitudinal load. Based on the performed FE analysis and strength tests of the wagon, it was verified that the most strenuous component of the wagon with a rotatable loading platform is a connector (lock) coupling the side of the rotatable platform with the over bogie part of the frame wagon. The selected aspects of numerical and experimental studies of the prototype railway wagon and its components are presented in the paper. FE analyses of the side lock element separated from the wagon structure are discussed as well.

Dynamic Analysis of Column Stand for Aircraft Multi-barrel Machine Gun with Consideration of Bearing Clearance

To build a machine gun on a helicopter board or on a vehicle, a sufficiently rigid and strong stand is required [2]. The construction of a column stand ensures changing a shot direction in the vertical plane and rotation in the horizontal plate. In a bearing of the column, a clearance can occur. It can cause a change in accuracy of a trajectory angle of the bullet. The paper presents a dynamic analysis of a machine gun taking into account clearance in the bearing. The target of the analysis is to find an impact of clearance on the trajectory angle of the bullet.

NUMERICAL TESTS OF THE DOUBLE SPRING WITH HANGERS

Subject of the work include selected numerical models of the test stand intended for testing a prototype double multi-leaf spring of bi-linear nature. Basic design assumptions of the stand were as follows: provide laboratory tests of multi-leaf (single and double) springs designed for dependent suspensions of passenger cars of permissible weight up to 3,5 tones. The stand should allow for testing basic spring and strength characteristics in the quasi-static conditions and dynamic conditions with the impact of the force impulse or a set variable load characterized by a particular force amplitude (displacement) and frequency of its variations. Considered stand models include the tested spring, base, support and the hanger. This paper presents two types of FEM models of the spring element (beam and 3D). In the first element, components of the spring-hanger system were mapped by means of beam elements, in the second one by means of definite solid elements. The spring was loaded with a vertical force from 0 to 10000 N. A nonlinear analysis of the bi-linear spring was carried out including clearance as well as the elastic analysis of the stand. The results of the numerical tests are presented in a form of tabular specifications, diagrams of displacements, and reduced stresses of selected components of the stand.

Numerical standard tests of railway carriage platform

The object of the paper is to build a numerical model of a railway wagon and perform statics calculation. The examined railway wagon is designed to transport interchangeable containers in ACTS (Abroll Container Transport System). The essential matter of such reloading is placing the container on a special rotating platform, which enables horizontal reloading of the load on the truck. The carriage is equipped with a flat frame cooperating with two bogies and three mobile platforms rotated in respect to central knots in order to simplify the process of loading and unloading of the interchangeable containers. A numerical model was verified and validated by experimental and numerical tests. Particular attention was paid to the support model in a contact place of the frame-carriage and bogies. The paper presents the results of static calculations prepared in accordance with relevant standards for this type of construction. The numerical model was loaded according to the requirements of PN-EN12663 standard specified for the F-I vehicle and BN-77/3532-40 standard. The finite element method was used for numerical analysis. A discreet FEM model was developed with the aid of MSC Patran pre-processor, while MSC Nastran code was applied for simulations. The results of calculations are presented by displacement and stress characteristic. Strength of construction was determined based on results.