Paweł Gotowicki

Numerical analysis of a shaped rail pad under selected static load

Numerical analysis of selected type of the polyurethane rail pad is presented in the paper. A shaped pad with cylindrical-shaped elements in its working section was selected as a representative for the computational simulation. Analysis reflected the experimental test according to the valid standard. The test included loading of the vertical force perpendicular to the foot of the rail. Such test allows determining the static stiffness of the pad. The Mooney – Rivlin material model was selected in the current study. Necessary experimental tests including a uniaxial compression and tension were conducted to provide material constants for the hyperelastic material model applied for the FE model. Simplified FE models of the considered rail pad and the rail were developed. Rounded corners and edges of the cylindrical-shaped elements were omitted, since their modelling required a significant density of the FE mesh. Vertical force perpendicular to the foot of the rail was declared as nodal force distributed evenly along the edges of the selected finite element models Non-linear static analysis was performed using MSC.Marc software with large displacements and deformations taken into consideration. The obtained results allowed estimating deformations and the state of stress in a highly deformed rail pad. The static stiffness of the pad was defined as secant stiffness based on the vertical force – deflection curve.

IDENTIFICATION OF LAYERS DISTRIBUTION IN THE COMPOSITE COUPON USING FINITE ELEMENT METHOD AND THREE POINT BENDING TEST

Abstract The main objective of the study is to develop experimentally validated FE model and perform numerical analysis of layered composites made by hand lay-up techniques during tension and bending test. The research object is glass - polyester laminate made of four unidirectional layers. In order to validate the numerical models experimental test were performed. Due to the very different stiffness modulus in tension and bending loading the material properties obtained from standard test are not suitable to apply in numerical model. Significantly different behaviour compared to experimental test was obtained for tree point bending where the numerical model becomes too stiff. Simple coupons, relatively easy to manufacture presented in the paper have very low quality. The differences in actual and theoretical bending stiffness (obtained from tension stiffness) exceed 70%. In order to represent the actual structure the layers of the composite were divided by resin layers and also additional resin layer at the top and bottom of the model were defined. Single stage optimization process was used to adjust the material layout. After layer set-up modification very significant improvement can be seen for flexural behaviour

Experimental Investigation of IED Interrogation Arm During Normal Operation and Mine Flail Structure Subjected to Blast Loading

The paper presents experimental static tests of IED interrogation arm for Shiba special vehicle. The test was performed by Military University of Technology and Military Institute of Engineer Technology. A number of strain gauges and camera markers were placed on the arm to allow recording strains and movements of specific construction points. The arm’s motion was recorded using high speed camera. The equipment used were Vishay EA 06 120LZ 120 strain gauges with ESAM Traveler bridge. The sampling rate was 1000 Hz. The test was to pick up maximum design weight, move it to maximum overhang and then drop it on the ground. During the test, signal from gauges and video capture was recorded. The data was then processed using TEMA 3D software to obtain markers displacements and angular changes of both arm parts. Afterwards, the test was repeated for different weight. The analysis showed, that maximum stresses in examined construction parts did not exceed yield stress of material. As well as that, in-depth motion analysis of the arm was conducted. Further works are twofold. Firstly, there will be tests concerning arm under dynamic load occurring during normal maintenance During this test only strains in specific construction parts will be recorded. Secondly, numerical model of an arm will be developed and validated using data obtained during both tests. This will help visualize stress distribution in each arm’s part

Experimental investigation of ied interrogation arm during normal operation

The paper presents experimental static tests of IED interrogation arm for Shiba special vehicle. The test was performed by Military University of Technology and Military Institute of Engineer Technology. A number of strain gauges and camera markers were placed on the arm to allow recording strains and movements of specific construction points. The arm’s motion was recorded using high speed camera. The equipment used were Vishay EA 06 120LZ 120 strain gauges with ESAM Traveller bridge. The sampling rate was 1000 Hz. The test was to pick up maximum design weight, move it to maximum overhang and then drop it on the ground. During the test, signal from gauges and video capture was recorded. The data was then processed using Thema 3D software to obtain markers displacements and angular changes of both arm parts. Afterwards, the test was repeated for different weight. The analysis showed, that maximum stresses in examined construction parts did not exceed yield stress of material. As well as that, in-depth motion analysis of the arm was conducted. Further works are twofold. Firstly, there will be tests concerning arm under dynamic load occurring during normal maintenance During this test only strains in specific construction parts will be recorded. Secondly, numerical model of an arm will be developed and validated using data obtained during both tests. This will help visualize stress distribution in each arm’s part.