Numerical Optimization for the Impact Performance of a Rubber Ring Buffer of a Train Coupler

Shock and vibration caused by mechanical motion bring huge potential threats to the service life and assembly reliability of mechanical systems. Rubber materials have been widely used in aircraft, trains, and other engineering fields, due to their excellent properties in shock and vibration absorption. This paper aimed to study the rubber ring buffer applied to a certain type of Chinese locomotive. Firstly, the finite element model was established and verified through experimental data. Based on the verified simulation model, the influence of the constitutive parameters (C01/C10 ratio height H and contour radius R) of the rubber ring on its energy absorption and peak crushing force under impact loading was studied in a numerical environment. Finally, the design of the experiment was carried out by the optimized Latin hypercube method, and the response surface model was established, which intuitively demonstrated the influence of the relevant parameters of the rubber ring on the change trend of the energy absorption and peak force. Based on the proxy model, the parameters that improve the crashworthiness of the rubber ring buffer were found quickly by the NSGA-II optimization algorithm, and the problems of a long calculation time and low optimization efficiency when using the conventional finite element method were avoided. The optimization results stated that when H = 107.57 mm and R = 85.70 mm, C01/C10 = 0.0571 of the energy absorption of the optimized buffer was increased by 59.03%, and the peak force was decreased by 14.37%, compared with the original structure. The optimized rubber ring buffer is expected to reduce the peak crushing force, enhance the energy absorption capacity, and mitigate the damage to the train system caused by shock and vibration.

A Novel Structure of Rubber Ring for Hydraulic Buffer Seal Based on Numerical Simulation

Landing gear is a key load-bearing structure of aircraft during ground operation, and the landing capacity of landing gear is determined by the performance of buffer. To solve the problem of buffer failure caused by insufficient static sealing of a rubber ring at groove side, a new structure of a butterfly rubber ring is proposed by analyzing the factors affecting sealing performance of the rubber ring. First, the constitutive equation of rubber material is derived based on the theory of hyper-elasticity, and the material parameters are obtained by fitting the experimental data. Then, by analyzing the simulation method of installation mode and installation stroke, the simulation method suitable for calculating the sealing performance of the rubber ring is established. The linear fitting formulas with Pearson coefficient greater than 0.92 are used to discuss the influence of pre-compression rate and hydraulic pressure on the sealing performance of the rubber ring. Compared with O-ring, the contact pressure of butterfly-ring is increased by 30% in assembly state and 14% in working state. The results show that the butterfly rubber ring has excellent static sealing performance. It is concluded that improving the configuration of the sealing ring can solve the insufficient unilateral sealing of the hydraulic buffer.

DIDACTIC POSSIBILITIES OF COMPUTER MODELING OF BODY MOVEMENT ON LESSONS AT PEDAGOGICAL UNIVERSITY

The didactic possibilities of the body movement modeling by replacing it with the material points system, which connected among themselves by weightless viscous elastic rods, are discussed. It is shown that the modeling of the body by a system of particles bound by viscoelastic weightless rods, obeying the basic law of dynamics, really allows: 1) to obtain the computer animation, i.e. the visual image of moving body at successive moments of time; 2) to plot the change of coordinates, velocities and accelerations of any of its points over time; 3) to model the translational, rotational, flat and spherical motion of the body, the interaction of the body with the surface or other body, to study the swimming of bodies, precession of the gyroscope and other phenomena; 4) to activate the mental activity of students, increase their motivation to learn. The tasks are considered: about collision of viscoelastic body with solid surface; about destruction of beam with defect; about the rotating wheel falling on surface; about flight of the rubber ring; about collision of two bodies; about the swimming of body with attached load; about the flexible ruler falling on cylinder; about the chain falling on cylinder; about the disk rotating on the horizontal surface; about the tumbling disk; about the gyroscope precession. The paper contains 8 figures obtained as a result of computer modeling of the above phenomena. As result of the analysis of the solved problems, it is shown that the modeling of a viscoelastic body by the method of bound particles has great didactic possibilities. It allows: 1) to study translational, rotational motion, deformation of bodies, gyroscope precession, etc., to update the knowledge of the relevant concepts and laws of mechanics; 2) to intensify the educational and cognitive activity of students, to increase their motivation for learning and its effectiveness; 3) to master the method of computer modeling, get acquainted with the solution of various professional tasks, explain the algorithms used and the simulation results at the school or pedagogical university level; 4) to develop the physical and algorithmic thinking, the ability to use the coordinate method and to perform information processing; 5) to organize an interactive dialogue between the student and the computer program; 6) to visualize information about the state of the object, build the trajectory of its points, the dependency graphs of coordinates and speeds on time; 7) to create various animations of body movement, to form a visual image of the corresponding phenomena; 8) to create problematic situations that require editing a computer program, changing system parameters, initial conditions and external influences; 9) to deepen the inter-subject connections between mathematics, physics and computer science.

Numerical Investigations on the Shape Optimization of Stainless-Steel Ring Joint with Machine Learning

Since pipes used for water pipes are thin and difficult to fasten using welding or screws, they are fastened by a crimping joint method using a metal ring and a rubber ring. In the conventional crimping joint method, the metal ring and the rubber ring are arranged side by side. However, if water leaks from the rubber ring, there is a problem that the adjacent metal ring is rapidly corroded. In this study, to delay and minimize the corrosion of connected water pipes, we propose a spaced crimping joint method in which metal rings and rubber rings are separated at appropriate intervals. This not only improves the contact performance between the connected water pipes but also minimizes the load applied to the crimping jig during crimping to prevent damage to the jig. For this, finite element analyses were performed for the crimp tool and process analysis, and the design parameters were set as the curling length at the top of the joint, the distance between the metal rings and rubber rings, and the crimp jig radius. Through FEA of 100 cases, data to be trained in machine learning were acquired. After that, training data were trained on a machine learning model and compared with a regression model to verify the model’s performance. If the number of training data is small, the two methods are similar. However, the greater the number of training data, the higher the accuracy predicted by the machine learning model. Finally, the spaced crimping joint to which the derived optimal shape was applied was manufactured, and the maximum pressure and pressure distribution applied during compression were obtained using a pressure film. This is almost similar to the value obtained by finite element analysis under the same conditions, and through this, the validity of the approach proposed in this study was verified.

PSI-41 Impacts of Flunixin Meglumine injection on wound score and swelling appearance of either rubber ring castrated and tail docked or surgically castrated and docked lambs

Our hypothesis was that administering Flunixin Meglumine (FM) to lambs that were either rubber ring castrated and docked (RR) or surgically castrated and emasculator docked (SC) would decrease swelling and wound appearance score. Rambouillet ram lambs (n = 181) were allocated in a completely randomized design in a 2 x 2 factorial arrangement of treatments to determine the effects of RR or SC and emasculator docking on ram lambs with administration of FM (2.2 mg/kg of BW) or saline (S; 2.2 mg/kg of BW). Wounds were assessed on days 4 and 7 post-treatment. The Wound Assessment Scale ranged from 1 – 5 and was determined from levels of discharge, scabbing, and wound healing. The swelling score was also a 1 - 5 scale, varying from no swelling, large amounts, or healed. Scrotal wound exhibited a treatment x day interaction (P < 0.001), however tail wound score (P = 0.84) and scrotal swelling (P = 0.36) were not affected. The SC treated lambs had a higher wound score on day 4 and 7 when compared to the RR treated lambs for both the scrotum and tail score (P < 0.001). Flunixin Meglumine had no effect on wound score of the scrotum (P > 0.50) and tail (P > 0.43) for both RR and SC groups. However, RR treated lambs had higher swelling scores on day 4 and 7 (P < 0.001). Flunixin Meglumine administration did not influence swelling score in treated lambs (P > 0.43). Surgical castration resulted in an increase in wound score compared to rubber ring castrated and docked lambs, but rubber ring castrated and docked lambs had an increase in wound swelling. Flunixin Meglumine did not have an impact on either wound score or wound swelling, regardless of castration method.

273 Impacts of Flunixin Meglumine injection on pain responses of either rubber ring castrated and tail docked or surgically castrated and docked lambs

Our hypothesis was that administering Flunixin Meglumine (FM) to lambs that were either rubber ring castrated and docked or surgically castrated and emasculator docked would decrease behavioral stress, serum cortisol and haptoglobin concentration, but increase average daily gain. Rambouillet ram lambs (n = 181) were allocated with a completely randomized design in a 2 x 2 factorial arrangement of treatments. Treatment combinations included rubber ring castration and tail docking (RR; placement of rubber band at distal end of caudal fold and around the base of the testicles) or surgical castration (SC; surgical scissors removing the lower third of the scrotum and testicles removed manually) and emasculator docking (crushing the tail at the distal end of the caudal fold, followed by cutting of the tail) on ram lambs with administration of saline (S) or FM (2.2 mg/kg of BW; RR-S, RR-FM, SC-S, SC-FM). Ram lambs were castrated at 12.5 ± 5.5 days of age and observed for behavioral changes such as lying down, leg extension and walking for 180 min in 30-min increments. Blood samples were taken at -30, 30, 90- and 140-minutes post-treatment to observe cortisol and haptoglobin levels. Behavioral traits, physiological traits, and average daily gain were analyzed in PROC GENMOD (SAS Inst. Inc., Cary, NC). A treatment x time interaction (P < 0.001) occurred for lamb pain behavioral scale, where scores at 30, 60, and 180 minutes after castration and docking exhibited differences among treatments. Average daily gain was not affected by a treatment x time interaction (P = 0.22) or treatment (P = 0.50) main effect. Serum cortisol concentration exhibited a treatment x time interaction (P = 0.002). The SC-FM lambs had lower cortisol concentrations (P = 0.004) than all other treatments at 90 min post-treatment, with the SC-S lambs having higher concentrations (P < 0.001) at 140 min post-treatment. Haptoglobin concentration did not exhibit a treatment x time interaction (P = 0.99); however, treatment and age were significant (P < 0.004). The RR-S lambs had an increase concentration of haptoglobin with SC-FM lambs being intermediate. Overall, results indicate that the method of castration and docking in lambs affected short lived behavioral and physiological stress, with the administration of FM decreasing stress regardless of castration and docking method.