This paper presents the capabilities of ABAQUS finite-element program [1] in modelling sandwich beams and plates resting on deformable foundations. Specific systems of sandwich beams and plates separated by an elastic core layer were subjected to the action of point and distributed moving loads. A few theoretical examples are provided to present different techniques of modelling the foundations and the moving loads. The effects of the boundary conditions and of the foundation parameters on the deflections of the analysed structures are also presented.
The paper analyses the influence of seasonal temperature variations on fatigue strength of flexible and semi-rigid pavement structures chosen for KR4 traffic flow category. The durability of pavement determined assuming a yearly equivalent temperature of 10˚C and assuming season-dependent equivalent temperatures was compared. Durability of pavement was determined with the use of Asphalt Institute Method and French Method. Finite Element Method was applied in order to obtain the strain and stress states by the means of ANSYS Mechanical software. Obtained results indicate a considerable drop in pavement durability if seasonal temperature variations are considered (up to 64% for flexible pavements and up to 80% for semi-rigid pavements). Durability obtained by the French Method presents lower dependence on the analysed aspect.
The article presents a constitutive model for Shape Memory Alloys (SMA) along with result of dynamic simulations of SMA model. The applications of devices incorporating SMA in civil engineering focus mostly on mitigation of the seismic hazard effects in new-build and historical buildings or improvement of fatigue resilience. The unique properties of SMA, such as shape memory effect and superelasticity give promising results for such applications. The presented model includes additional phenomenon of SMA – internal loops. The paper shows the method of formulation of physical relations of SMA based on special rheological structure, which includes modified Kepes’s model. This rheological element, introduced as dual-phase plasticity body, is given in the context of martensite phase transformation. One of the advantages of such an approach is a possibility of formulation of constitutive relationships as a set of explicit differential equations. The application of the model is demonstrated on example of dynamic simulations of three dimensional finite element subjected to dynamic excitation.
The paper presents results of numerical calculations of a diaphragm wall model executed in Poznań clay formation. Two selected FEM codes were applied, Plaxis and Abaqus. Geological description of Poznań clay formation in Poland as well as geotechnical conditions on construction site in Warsaw city area were presented. The constitutive models of clay implemented both in Plaxis and Abaqus were discussed. The parameters of the Poznań clay constitutive models were assumed based on authors’ experimental tests. The results of numerical analysis were compared taking into account the measured values of horizontal displacements.
The paper presents selected aspects of dynamic numerical simulations of an orthotropic steel railway bridge loaded by high-speed trains. The model of moving loads was adopted in accordance with the models set out in the applicable standards. The current European code requirements are referred in which the computer calculations of the dynamic response of the structure are the basis for assessing the suitability of the structure to carry high-speed rail traffic ( v > 160 km/h ). In this research the calculations are based on the author's method of generating traffic roads in Abaqus FEM environment. lt is emphasized in the paper that in most commercial FEM codes (including Abaqus), moving loads are not implemented in modules responsible for defining of loads. The author's approach to this issue allowed to obtain results confirming its adequacy. In the longer term, the authors will develop a plan to adapt this algorithm in order to generale traftic loads on bridges discretized as spatial and plane numerical models.
The paper presents results of the laboratory tests made for the prototype resilient under sleeper pads in the Warsaw University of Technology laboratory unit. These pads are dedicated to reduce vibrations transmitted to the vicinity of the railroad and to improve the resistance of the railroad structure. The laboratory testing program was carried out for elastomeric materials (polyurethane and rubber based) due to the PN-EN 16730 standard. The obtained values of the key parameters were used in order to determine the insertion loss vibration level by applying analytical method. The paper presents the influence of selected parameters i.e. static and dynamic moduli on the reduction of vibration and structure-borne sound level.
The article presents an assessment of the suitability of the cone penetrometer to determine the soil state. The work describes the principle of the device operation, which is similar to commonly used dynamic DPL probes. Then, the results of research conducted in Polish conditions using the new conical penetrometer were presented. A series of measurements were performed in real field conditions. On their basis, an attempt was made to correlate the results obtained with a conical penetrometer and a static probe CPT. Then, the obtained correlations were validated. On this basis preliminary evaluation of the conical penetrometer suitability for the soil state determining.
The present paper discusses static and dynamic characteristics of various under sleeper pads (USP) that are to be used in the ballasted track systems as resilient vibroacoustic isolators. Four different USP samples were put to fatigue tests and static and dynamic bedding moduli were determined. The purpose of the tests, which were carried out up to 500 thousand load cycles, was to determine which USP have favourable and which unfavourable properties, taking into account their potential application as the elements used for energy dissipation and reduction of noise and vibration. The obtained results allowed the authors to indicate samples with a potential for further analysis and to reject those, which did not satisfy the adopted criteria.
The dynamic analyses are of key importance in the cognitive process in terms of the correct operation of structures loaded with time alternating forces. The development of vehicle industry, which directly results in an increase in the speed of moving vehicles, forces the design of engineering structures that ensure their safe use. The authors of the paper verified the influence of speed and vehicle parameters such as mass, width of track of wheels and their number on the values of displacements and accelerations of selected bridge elements. The problem was treated as the case study, because the analyses were made for one bridge and the passage of three types of locomotives. The response of the structure depends on the technological solutions adopted in the bridge, its technical condition, as well as the quotient of the length of the object and vehicle. A new bridge structure was analyzed and dynamic tests were carried out for trainsets consisting of one and two locomotives. During the actual dynamic tests, the structure was loaded with a locomotive moving at a maximum speed of 160 km/h.