Relationships Between Wheel/Rail Surface Impact Loadings and Correspondingly Transmitted Tie/Ballast Impact Pressures for Revenue Train Operations

2018 ◽  
Author(s):  
Travis J. Watts ◽  
Jerry G. Rose ◽  
Ethan J. Russell
Keyword(s):  
Test Section ◽  
Impact Load ◽  
Peak Force ◽  
Pressure Measurements ◽  
Track Geometry ◽  
Impact Forces ◽  
Interfacial Pressure ◽  
Degradation Rates ◽  
The Stability ◽  
The Impact

A series of specially designed granular material pressure cells were precisely positioned directly below the rail at the tie/ballast interface to measure typical interfacial pressures exerted by revenue freight trains. These vertical pressures were compared to the recorded wheel/rail nominal and peak forces for the same trains traversing nearby mainline wheel impact load detectors (WILDs). The cells were imbedded within the bottom of new wood ties so that the surfaces of the pressure cells were even with the bottoms of the ties and the underlying ballast. The cells were inserted below consecutive rail seats of one rail to record pressures for a complete wheel rotation. The stability and tightness of the ballast support influenced the magnitudes and consistencies of the recorded ballast pressures. Considerable effort was required to provide consistent ballast conditions for the instrumented ties and adjacent undisturbed transition ties. Norfolk Southern (NS) crews surfaced and tamped through the test section and adjacent approach ties. This effort along with normal accruing train traffic subsequently resulted in reasonably consistent pressure measurements throughout the test section. The impact ratio (impact factor) and peak force values recorded by the WILDs compared favorably with the resulting magnitudes of the transferred pressures at the tie/ballast interface. High peak force and high impact ratio WILD readings indicate the presence of wheel imperfections that increase nominal forces at the rail/wheel interface. The resulting increased dynamic impact forces can contribute to higher degradation rates for the track component materials and more rapid degradation rates of the track geometry. The paper contains comparative WILD force measurements and tie/ballast interfacial pressure measurements for loaded and empty trains. Typical tie/ballast pressures for locomotives and loaded freight cars ranges from 20 to 30 psi (140 to 210 kPa) for smooth wheels producing negligible impacts. The effect of increased wheel/rail impacts and peak force values on the correspondingly transmitted pressures at the tie/ballast interface is significant, with increased pressures of several orders of magnitude compared to nominal impact forces from wheels.

Research on the Mechanical Properties and Energy Consumption Transfer Law of Cement Tailings Backfill Under Impact Load

2021 ◽  
Vol 13 (5) ◽  
pp. 889-898
Author(s):  
Yong-Ye Mu ◽  
Xiang-Long Li ◽  
Jian-Guo Wang ◽  
Zhi-Gao Leng
Keyword(s):  
Mechanical Properties ◽  
Energy Transfer ◽  
Impact Load ◽  
Peak Stress ◽  
Peak Strain ◽  
Impact Compression ◽  
Average Strain Rate ◽  
Failure Morphology ◽  
The Stability ◽  
The Impact

The cemented tailings backfill (CTB), which plays a significant role in the stability of mine structure, is made of cement, tailings, and water in a certain proportion. When blasting and excavating an underground mine, the CTB will be disturbed by blasting. The impact load of blasting has an impact on the stability of the CTB, which is directly related to the safety of mine construction. The mechanical behaviour of CTB is generally affected by the cement-tailings ratio (C/T) and average strain rate (ASR). Therefore, a series of impact experiments were carried out on three CTB specimens with different C/T using a SHPB. Combined with the experimental results, this account reports studies on the effects of C/T and ASR on the mechanical properties of CTB, and on the energy transfer laws of CTB during impact compression. The research results show that when the ASR is less than 70 s−1, the peak stress and the peak strain have the same trend, and both of them continue to increase with the increase of ASR.When the ASR exceeds 70 s−1, as the ASR increases, the peak stress continues to increase, but the peak strain decreases gradually. Afterwards, the law of energy transfer of the CTB specimen was analyzed. It was found that as the incident energy increased, the energy reflection ratio of the CTB increased. Both the energy transmitted ratio and the energy dissipation ratio decreased. The volumetric energy showed a sharp increase first and then a trend Because of the slowly increasing trend. Finally, according to the failure morphology of the CTB, it is found that the ASR and the C/T together affect the failure of the CTB. The failure model of the CTB is mainly split failure and crush failure.

scholarly journals Study on Dynamic Behavior of Bridge Pier by Impact Load Test Considering Scour

2020 ◽  
Vol 10 (19) ◽  
pp. 6741
Author(s):  
Myungjae Lee ◽  
Mintaek Yoo ◽  
Hyun-Seok Jung ◽  
Ki Hyun Kim ◽  
Il-Wha Lee
Keyword(s):  
Natural Frequency ◽  
Evaluation Method ◽  
Impact Load ◽  
Full Scale ◽  
Load Test ◽  
Scale Model ◽  
Second Mode ◽  
Surcharge Load ◽  
The Stability ◽  
The Impact

In this study, for the establishment of a safety evaluation method, non-destructive tests were performed by developing a full-scale model pier and simulating scour on the ground adjacent to a field pier. The surcharge load (0–250 kN) was applied to the full-scale model pier to analyze the load’s effect on the stability. For analyzing the pier’s behavior according to the impact direction, an impact was applied in the bridge axis direction, pier length direction, and pier’s outside direction. The impact height corresponded to the top of the pier. A 1-m deep scour was simulated along one side of the ground, which was adjacent to the pier foundation. The acceleration was measured using accelerometers when an impact was applied. The natural frequency, according to the impact direction and surcharge load, was calculated using a fast Fourier transform (FFT). In addition, the first mode (vibratory), second mode (vibratory), and third modes (torsion) were analyzed according to the pier behavior using the phase difference, and the effect of the scour occurrence on the natural frequency was analyzed. The first mode was most affected by the surcharge load and scour. The stability of the pier can be determined using the second mode, and the direction of the scour can be determined using the third mode.

scholarly journals RESPONSE OF SEADYKES DUE TO WAVE IMPACTS

1976 ◽  
Vol 1 (15) ◽  
pp. 149 ◽  
Author(s):  
A. Fuhrboter ◽  
H.H. Dette ◽  
J. Grune
Keyword(s):  
Laboratory Data ◽  
Breaking Waves ◽  
Scale Model ◽  
Small Scale ◽  
Air Entrapment ◽  
Small Areas ◽  
Impact Forces ◽  
The Stability ◽  
Short Time ◽  
The Impact

Damages on seadykes and revetments are mainly caused by wave impacts due to breaking waves. These impact forces act on small areas for a very short time and cause crater-like formations, when the forces are transmitted instantaneously to the side-walls of cracks in the cover of dykes or through joints into and below revetments. In this paper the results of investigations on impact forces are presented. A comparison of field data and laboratory data proves considerable differences, which must be explained mainly by the different air entrapment for prototype and small-scale conditions in the breaking waves. Both the data from field and small-scale model emphasize, that the slope of the dyke or revetment is responsible at first for frequency and magnitude of the impact forces. Furthermore the effect of impact forces is demonstrated by the results of investigations on the stability of stone revetments with joints.

scholarly journals Dynamic Wheel-Rail Force-Based Track-Irregularity Evaluation for Ballasted Track on Serviced Railway by Adjacent Excavation

2021 ◽  
Vol 12 (1) ◽  
pp. 375
Author(s):  
Jung-Youl Choi ◽  
Dong-Ryong Park ◽  
Jee-Seung Chung ◽  
Sun-Hee Kim
Keyword(s):  
Impact Load ◽  
Field Measurements ◽  
Interaction Force ◽  
Wheel Load ◽  
Track Geometry ◽  
Railway Line ◽  
Before And After ◽  
Track Irregularity ◽  
The Impact ◽  
Track Irregularities

This study investigates a load-based, track-irregularity-analysis technique for ballasted tracks on a serviced railway line with respect to excavation work conducted in adjacent sites. A numerical analysis and field measurements (railbed-settlement-monitoring sensor, track-geometry-measurement system, wheel-load measurements) were analyzed comparatively to demonstrate the correlation between the track irregularities and the Wheel-Rail interaction force. In this way, we highlight the necessity for load-based track-irregularity-management methods. The analyzed results show that the maximum dynamic wheel load was measured in the range of approximately 10 m before and after the location where the maximum track irregularities occurred, and that even if the maintenance criteria of track irregularities were satisfied, the design dynamic wheel load could still be exceeded depending on the train speed, thus indicating that track damage can be caused by the impact load.

scholarly journals Soft projectile impact forces measurement using Hopkinson bars: application to ice, artificial bird and rubber

2021 ◽  
Vol 250 ◽  
pp. 01008
Author(s):  
Ramón del Cuvillo ◽  
Jose Alfonso Artero-Guerrero ◽  
Jesús Pernas-Sánchez ◽  
Jorge López Puente
Keyword(s):  
Kinetic Energy ◽  
High Speed ◽  
Soft Materials ◽  
Peak Force ◽  
Video Cameras ◽  
Impact Forces ◽  
Compression Strain ◽  
Experimental Campaign ◽  
The Impact ◽  
Semiconductor Strain

This work presents an experimental campaign of impacts of soft projectiles to measure the induced force during the impact. Three different materials acting as soft impactors that could strike against a aeronautical structural component: ice, artificial bird and rubber have been impacted at several velocities against an aluminium Hopkinson bar. This device has been instrumented with semiconductor strain gauges that allow to obtain the induced compression strain. Additionally, all the impacts were recorded using high-speed video cameras, allowing the kinematic analysis of the projectile during the impact. After the results study, it has been concluded that there is a linear dependency between the kinetic energy and the peak force for all three materials. Added to that, it has been proved that the higher peak force corresponds to ice, despite the kinetic energy, followed by rubber and finally the artificial bird. In addition, while ice and artificial bird projectiles get radially dispersed after the impact, rubber spheres rebound due to its different behaviour. The obtained data is of great interest to design structures which could be subjected to impacts of soft materials such as aeronautic structures

Simulation Based Reduction of the Impact Load Occurring in the Moment of Cutting Edge Entrance in Order to Prolong Tool-Life

2016 ◽  
Vol 1140 ◽  
pp. 173-180
Author(s):  
Boris Matuschka ◽  
Nikolay Boev ◽  
Frederik Zanger ◽  
Volker Schulze
Keyword(s):  
Simulation Model ◽  
Tool Life ◽  
Cutting Tool ◽  
Impact Load ◽  
Cutting Edge ◽  
Machining Processes ◽  
Impact Forces ◽  
Simulation Based ◽  
The Moment ◽  
The Impact

High mechanical impact loads in interrupted or inhomogeneous machining processes frequently lead to spontaneous fracture of the cutting edge. Even modern cutting materials cannot provide a combination of high enough hardness and toughness that is capable of preventing this sort of tool failure. Such machining conditions therefore remain difficult and further investigations, aiming to reduce the impact load of the cutting tool in order to enhance tool-life, are necessary. A simulation model of the impact situation, that serves to optimize a force conducting structure with regard to elasticity, damping properties and resulting force peaks, was developed and is presented in this paper. Furthermore measurement devices were composed that are needed for high-resolution recording of impact forces without repercussions and for verification of the elaborated simulation model. It could be shown that mechanical damping of the cutting tool can lead to reduced impact forces on the cutting edge, which in turn should lead to longer tool life.

Application of Granular Material Pressure Cells to Measure Railroad Track Tie/Ballast Interfacial Pressures

2018 ◽  
Vol 2672 (10) ◽  
pp. 146-155 ◽  
Author(s):  
Jerry G. Rose ◽  
David B. Clarke ◽  
Qinglie Liu ◽  
Travis J. Watts
Keyword(s):  
Granular Material ◽  
Granular Materials ◽  
Test Section ◽  
Pressure Measurements ◽  
Railroad Track ◽  
Considerable Effort ◽  
Minimal Impact ◽  
Active Surfaces ◽  
Impact Forces ◽  
Multiple Cells

This paper describes the development of a method to measure railroad track tie/ballast interfacial pressures using pressure cells specially designed for granular materials. Repeat measurements were taken during a several-month period on a Norfolk Southern Corporation high-tonnage mainline. The research employed new wood crossties routed so pressure cells could be recessed within the ties. Thus, the active surfaces of the pressure cells were flush with the tie bottoms. Cabling was run through a recess to the tie end. This greatly reduced the likelihood of damage to the instrumentation during track surfacing and lining activity. The ties were installed such that multiple cells were directly under consecutive rail seats of one rail. Several ties also had cells either at the center or the rail seat of the opposite rail. The researchers expended considerable effort to provide consistent ballast conditions for the instrumented ties and adjacent, undisturbed (transition) ties. Norfolk Southern crews surfaced and tamped through and on either side of the test section. This, plus consolidation through normal accruing train traffic, resulted in consistent measurements through the section. The paper presents ballast pressure magnitudes and distributions and discusses results, including the effects of variable ballast support, wheel loadings, and impact loadings. Typical vertical ballast pressure measurements directly under the rail seat, with compacted ballast and minimal impact forces ranged from 20 to 30 psi (140 to 210 kPa) under the heaviest common revenue wheel loadings.

Ranking of Biomechanical Metrics to Describe Human Response to Impact-Induced Damage

2018 ◽  
Author(s):  
Nicholas DeVogel ◽  
Anjishnu Banerjee ◽  
Frank A. Pintar ◽  
Narayan Yoganandan
Keyword(s):  
Impact Load ◽  
Predictive Ability ◽  
Peak Force ◽  
Brier Score ◽  
Published Data ◽  
Statistical Process ◽  
Time To Peak ◽  
Impact Biomechanics ◽  
Observed Damage ◽  
The Impact

Determination of human tolerance to impact-induced damage or injury is needed to assess and improve safety in military, automotive, and sport environments. Impact biomechanics experiments using post mortem human surrogates (PMHS) are routinely used to this objective. Risk curves representing the damage of the tested components of the PMHS are developed using the metrics gathered from the experimental process. To determine the metric that best explains the underlying response to the observed damage, statistical analysis is required of all the output response metrics (such as peak force to injury) along with the examination of potential covariates. This is conducted by parametric survival analysis. The objective of this study is to present a robust statistical methodology that can be effectively used to achieve these goals by choosing the best metric explaining injury and provide a ranking of the metrics. Previously published data from foot-ankle-lower leg experiments were used with two possible forms of censoring: right and left censoring or right and exact censoring, representing the no injury and injury data points in a different manner. The statistical process and scoring scheme were based on the predictive ability assessed by the Brier Score Metric (BSM) which was used to rank the metrics. Response metrics were force, time to peak, and rate. The analysis showed that BSM is effective in incorporating different covariates: age, posture, stature, device used to deliver the impact load, and the personal protective equipment (PPE), i.e., military boot. The BSM-based analysis indicated that the peak force was the highest ranked metric for the exact censoring scheme and the age was a significant covariate, and that peak force was also the highest ranked metric for the left censored scheme and the PPE covariate was statistically significant. IRCs are presented for the best metric.

Dietary Vitamin and Stability of Oral Anticoagulation: Proposal of a Diet with Constant Vitamin K1 Content

1997 ◽  
Vol 77 (03) ◽  
pp. 504-509 ◽  
Author(s):  
Sarah L Booth ◽  
Jacqueline M Charnley ◽  
James A Sadowski ◽  
Edward Saltzman ◽  
Edwin G Bovill ◽  
...  
Keyword(s):  
Dietary Intake ◽  
Vitamin K ◽  
High Performance ◽  
Case Reports ◽  
Food Composition ◽  
Dietary Guidelines ◽  
Dietary Vitamin ◽  
Vitamin K1 ◽  
The Stability ◽  
The Impact

SummaryCase reports cited in Medline or Biological Abstracts (1966-1996) were reviewed to evaluate the impact of vitamin K1 dietary intake on the stability of anticoagulant control in patients using coumarin derivatives. Reported nutrient-drug interactions cannot always be explained by the vitamin K1 content of the food items. However, metabolic data indicate that a consistent dietary intake of vitamin K is important to attain a daily equilibrium in vitamin K status. We report a diet that provides a stable intake of vitamin K1, equivalent to the current U.S. Recommended Dietary Allowance, using food composition data derived from high-performance liquid chromatography. Inconsistencies in the published literature indicate that prospective clinical studies should be undertaken to clarify the putative dietary vitamin K1-coumarin interaction. The dietary guidelines reported here may be used in such studies.

IMPACT OF GOVERNMENT DEBT ON FINANCIAL SECURITY OF UKRAINE

2017 ◽  
Author(s):  
Olena Pikaliuk ◽  
◽  
Dmitry Kovalenko ◽  
Keyword(s):  
Economic Development ◽  
Public Debt ◽  
Positive Impact ◽  
The State ◽  
Financial Security ◽  
State Budget ◽  
The Public ◽  
Debt Security ◽  
The Stability ◽  
The Impact

One of the main criteria for economic development is the size of the public debt and its dynamics. The article considers the impact of public debt on the financial security of Ukraine. The views of scientists on the essence of public debt and financial security of the state are substantiated. An analysis of the dynamics and structure of public debt of Ukraine for 2014-2019. It is proved that one of the main criteria for economic development is the size of public debt and its dynamics. State budget deficit, attracting and using loans to cover it have led to the formation and significant growth of public debt in Ukraine. The volume of public debt indicates an increase in the debt security of the state, which is a component of financial security. Therefore, the issue of the impact of public debt on the financial security of Ukraine is becoming increasingly relevant. The constant growth and large amounts of debt make it necessary to study it, which will have a positive impact on economic processes that will ensure the stability of the financial system and enhance its security.

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