New support roller profile design for railway wheel re-profiling process by under-floor lathes with a single cutting tool

The wheel re-profiling is an important part of railway wheelset maintenance. Researchers and railway operators have been very concerned about how to minimize the loss of time during wheel re-profiling without decreasing safety. Avoiding wheelset disassembly means considerable time savings, while reducing wheel damage during operation. Underfloor wheel lathes are the most appropriate tool to achieve this double objective, and therefore the most used nowadays. Multi-cut tool lathes have the disadvantage of being extremely expensive. On the other hand, with single tool lathes, re-profiling is not smooth or safe enough when current convex profile support rollers are used. It is well known by the companies that during reprofiling the wheel suffers impacts/damaged. In this article, a methodology to optimize the profile of the support rollers used in underfloor single tool lathes for railway wheel re-profiling is proposed. This novel profile design will minimize damage and increase the safety of such lathes, since it proposes a greater smoothness in the process. Simulations of re-profiling process have been carried out by the finite element method showing that the designed roller profile reduces drastically the impact/damage during the operation. The impact generated between the re-profiling wheel and the rollers is avoided. Profile-optimized support rollers have been used in a real underfloor wheel lathe, showing good results.

METHOD OF CALCULATION THE STABILITY OF AN EXCAVATOR EQUIPPED WITH A CONE ROLLER

The construction and method of calculating the stability of a crawler excavator equipped with a new working body (cone roller) are considered. The calculation is made on two working positions (longitudinal and transverse) of the excavator, provided that the excavator must apply the maximum force on the working body at an angle of 90°. The force applied by the excavator boom to the cone roller during the introduction depends on the physical and mechanical properties of the compacted soil. The calculation method differs in that during the compaction of the roadbed, the cone sinks into the ground, and the excavator tends to roll in the direction of the rear track support roller, in contrast to the traditional danger of tipping over the front support roller when working with a bucket.

New Support Roller Profile Design for Railway Wheel Re-profiling Process by Under-floor Lathes With a Single Cutting Tool

The wheel re-profiling is an important part of railway wheelset maintenance. Researchers and railway operators have been very concerned about how to minimize the loss of time during wheel re-profiling without decreasing safety. Avoiding wheelset disassembly means considerable time savings, while reducing wheel damage during operation. Underfloor wheel lathes are the most appropriate tool to achieve this double objective, and therefore the most used nowadays.Multi-cut tool lathes have the disadvantage of being extremely expensive. On the other hand, with single tool lathes, re-profiling is not smooth or safe enough when current convex profile support rollers are used.In this article, a methodology to optimize the profile of the support rollers used in underfloor single tool lathes for railway wheel re-profiling is proposed. This novel profile design will minimize damage and increase the safety of such lathes, since it proposes a greater smoothness in the process. Simulations of re-profiling process have been carried out by the finite element method showing that the designed roller profile reduces drastically the impact/damage during the operation. Profile-optimized support rollers have been used in a real underfloor wheel lathe, showing good results.

Development of a nomogram to predict the contact stress between an I-girder and a support roller

The incremental launching method (ILM) is an efficient method of bridge construction primarily suited for environmentally sensitive areas. However, during the bridge launching, there are significant contact stresses between the launching system and the steel bridge girders. These substantial contact stresses can cause damage both on, and just under, the girder surface. Although Hertz contact theory solutions may give an insight into the problem, the accuracy is uncertain due to the presence of complex geometries, loads, and material properties. The complicated structural systems need to rely on numerical modeling such as the finite element analysis which are not always available. The primary objective of this study is to estimate the relationship of the maximum contact stress between an I-girder and a roller using a nomogram. The nomogram is built based on a parametric study with various roller dimensions and loads by numerical modeling. The maximum contact stress from the nomogram can be a useful tool in designing a bridge girder on a support roller.

Analysis of Functionally Graded Timoshenko Beams by Using Peridynamics

In this study, a new peridynamic formulation is presented for functionally graded Timoshenko beams. The governing equations of the peridynamic formulation are obtained by utilising Euler-Lagrange equation and Taylor’s expansion. The proposed formulation is validated by considering a Timoshenko beam subjected to different boundary conditions including pinned support-roller support, clamped-roller support and clamped-free boundary conditions. Results from peridynamics are compared against finite element analysis results. A very good agreement is obtained for transverse displacements, rotations and axial displacements along the beam.

The Results of Field Tests of an Onion Set Harvesting Machine Equipped with a Shaker Arrangement Asymmetrical Bar Elevator

Introduction. Machines for harvesting roots and onions do not provide qualitative indices of root heap separation that leads to violation of technical requirements during harvesting. New solutions are needed to increase the quality of root separation, increase the quality of separation and reduce damage. Materials and Methods. The article presents the design of the onion set harvesting machine. The machine is equipped with a bar elevator with asymmetrical arrangement of shakers. The technique and results of field research to determine the quality of set onion separation at the experimental rod elevator are described. Results. The results of production research of the onion set harvesting machine showed qualitative performance of the technological process of separating onion heap at optimal values of parameters: center distance between elliptical shaker and supporting roller 0.36-0.4 m at full separation of 97.0-97.2% and onion damage 1.65-1.68%; forward speed of rod elevator with asymmetrical arrangement of elliptical shaker and supporting roller 1.6 m/s at full separation of 98.5% and bulb damage 1.3%. Discussion and Conclusion. The use of a bar elevator with an asymmetrical arrangement of the elliptical shaker and support roller allows, in comparison with the symmetrical arrangement of shakers, an increase in bulb separation by 2.0% and a decrease in onion damage by 1.1%.

Ultrasonic welding of polymer fi lms

The choice of the method of ultrasonic welding of polymer fi lms is substantiated, its advantages over other welding methods are noted.It is shown that the parameters determining the performance of seam ultrasonic welding process for polymer fi lms are the amplitude of the waveguide oscillations, the welding static pressure and the speed of welding with a fi xed gap on a rotating support roller with self-stabilization of the welding seam thickness.

The Development of Technology and Equipment for Ultrasonic Seam Welding of Synthetic Fabrics

In this work, possible methods of ultrasonic welding of synthetic fabrics are considered and analyzed. Technological features of ultrasonic seam welding of synthetic fabrics are described. The key parameters of this type of welding that significantly influence the speed of achieving the maximum temperature in the fabric welding zone are identified. These parameters determine the intensity of the fabrics’ warm-up, and therefore, the efficiency of the welding process. Thermal processes occurring at seam welding of synthetic fabrics are studied. It is established that the welding time increases with an increase in the number of connecting layers as well as with addition of cotton to the fabric composition. It is determined that when welding synthetic fabrics of small thickness, heat removal to the waveguide and the support roller has virtually no influence on the maximum temperature at the border of the mating surfaces and on the time of achieving the maximum temperature. Experiments on welding lavsan, kapron and polypropylene fabrics are conducted. The dependence of the statistic welding pressure on the welding speed and the fixed gap between the waveguide and the support roller is investigated. It is determined that the movement of material under the waveguide doesn not have a warming-up impact on the neighbouring areas of the welded seam. The strength of the welded joints practically does not depend on the height and shape of the support roller.

PENGARUH NORMALIZING TERHADAP BAJA 20Mn Cr6 HASIL PENGECORAN UNTUK SUPPORT ROLLER

Rotary Kiln machine is used in fertilizer plant which is function to mix the fertilizer ingredients. Part of the Rotary Kiln is support by using a roller. Support roller is made of 20MnCr6 material, AISI 5120 (0.18% C) with casting process. Normalizing phase on casting processes is using to increase strength of the material The objectives of the normalizes process is to eliminate residual stresses, softening, increasing toughness, homogenization of micro structures and to ease machining processes. The effect of normalizing can be measured by using mechanical test, ie tensile test, hardness test and microstructure analysis. Test specimens were made the same material with normalizing and without normalizing process. Normalizing process temperature at 900oC heating for 150 minutes with air cooling for 7 hours. The results has shown that normalizing material has lowest tensile strength of 41.05 kgf/mm2 is compared to 42.16 kgf/mm2. However, the ductile fracture is higher 41.2% is compared to 29.52%, the microstructure formed uniformly evenly compared without normalizing. The softening process also makes the roller support rotate due to rubbing with riding ring.