scholarly journals A Dynamic Test of a Collision Post of a State-of-the-Art End Frame Design

2008 ◽  
Author(s):  
Michelle Priante ◽  
Patricia Llana ◽  
Karina Jacobsen ◽  
David Tyrell ◽  
Benjamin Perlman
Keyword(s):  
State Of The Art ◽  
Impact Load ◽  
Dynamic Test ◽  
Frame Structure ◽  
Critical Position ◽  
Frame Design ◽  
Equipment Safety ◽  
Grade Crossing ◽  
Space State ◽  
The Impact

In support of the Federal Railroad Administration’s (FRA) Railroad Equipment Safety Program, a full-scale dynamic test of a collision post of a state-of-the-art (SOA) end frame was conducted on April 16, 2008. The purpose of the test was to evaluate the dynamic method for demonstrating energy absorption and graceful deformation of a collision post. The post aims to protect the operators and passengers in the event of a collision where only the superstructure, not the underframe, is loaded. Methods for improving the performance of collision and corner posts were prompted by accidents such as the fatal collision in Portage, Indiana in 1998, where a coil of steel sheet metal penetrated the cab car through the collision post. The improvements made for the SOA end frame structure include more substantial corner and collision posts, robust post connections to the buffer beam and anti-telescoping (AT) beam, and corner and collision posts integrated with a shelf and bulkhead sheet. Full length side sills improved support for the end frame. This test focused on one collision post because of its critical position in protecting the operator and passengers in an impact with an object at a grade-crossing. For the test, a 14,000-lb cart impacted a standing cab car at a speed of 18.7 mph. The cart had a rigid coil shape mounted on the leading end that concentrated the impact load on the collision post. The requirements for protecting the operator’s space state that there will be no more than 10 inches of longitudinal crush and none of the attachments of any of the structural members separate. During the test, the collision post deformed approximately 7.4 inches and absorbed approximately 138,000 ft-lb of energy. The attachment between the post and the AT beam remained intact. The connection between the post and the buffer beam did not completely separate, however the forward flange and both side webs fractured. The post itself did not completely fail. There was material failure in the back and the sides of the post at the impact location. Overall, the end frame was successful in absorbing energy and preserving space for the operators and the passengers.

scholarly journals Dynamic and Quasi-Static Grade Crossing Collision Tests

2009 ◽  
Author(s):  
Michelle Mu¨hlanger ◽  
Patricia Llana ◽  
David Tyrell
Keyword(s):  
Energy Absorption ◽  
Impact Load ◽  
Dynamic Test ◽  
Full Scale ◽  
Structural Deformation ◽  
Longitudinal Deformation ◽  
Static Tests ◽  
Static Test ◽  
Grade Crossing ◽  
The Impact

To support the development of a proposed rule [1], a full-scale dynamic test and two full-scale quasi-static tests have been performed on the posts of a state-of-the-art (SOA) end frame. These tests were designed to evaluate the dynamic and quasi-static methods for demonstrating energy absorption of the collision and corner posts. The tests focused on the collision and corner posts individually because of their critical positions in protecting the operator and passengers in a collision where only the superstructure, not the underframe, is loaded. There are many examples of collisions where only the superstructure is loaded. For the dynamic test, a 14,000-lb cart impacted a standing cab car at a speed of 18.7 mph. The cart had a rigid striking surface in the shape of a coil mounted on the leading end that concentrated the impact load on the collision post. During the dynamic test the collision post deformed approximately 7.5 inches, and absorbed approximately 137,000 ft-lbs of energy. The SOA collision post was successful in preserving space for the operators and the passengers. For the quasi-static test of the collision post, the collision post was loaded in the same location and with the same fixture as the dynamic test. The post absorbed approximately 110,000 ft-lb of energy in 10 inches of permanent, longitudinal deformation. For the quasi-static test of the corner post, the post was loaded at the same height as the collision post, with the same fixture. The corner post absorbed 136,000 ft-lb of energy in 10 inches of permanent, longitudinal deformation. The series of tests was designed to compare the dynamic and quasi-static methods for measuring collision energy absorption during structural deformation as a measure of crashworthiness. When properly implemented, either a dynamic or quasi-static test can demonstrate the crashworthiness of an end frame.

scholarly journals Collapse Behaviour of a Concrete-Filled Steel Tubular Column Steel Beam Frame under Impact Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Lian Song ◽  
Hao Hu ◽  
Jian He ◽  
Xu Chen ◽  
Xi Tu
Keyword(s):  
Finite Element ◽  
Impact Loading ◽  
Mechanical Performance ◽  
Impact Load ◽  
Frame Structure ◽  
Actual Condition ◽  
Transverse Impact ◽  
Time Curve ◽  
Finite Element Software ◽  
The Impact

The progressive collapse of a concrete-filled steel tubular (CFST) frame structure is studied subjected to impact loading of vehicle by the finite-element software ABAQUS, in the direct simulation method (DS) and alternate path method (AP), respectively. Firstly, a total of 14 reference specimens including 8 hollow steel tubes and 6 CFST specimens were numerically simulated under transverse impact loading for verification of finite-element models, which were compared with the existing test results, confirming the overall similarity between them. Secondly, a finite-element analysis (FEA) model is established to predict the impact behaviour of a five-storey and three-span composite frame which was composed of CFST columns and steel beams under impact vehicle loading. The failure mode, internal force-time curve, displacement-time curve, and mechanical performance of the CFST frame were obtained through analyzing. Finally, it is concluded that the result by the DS method is closer to the actual condition and the collapse process of the structure under impact load can be relatively accurately described; however, the AP method is not.

scholarly journals Structural Crashworthiness Standards Comparison: Grade-Crossing Collision Scenarios

2009 ◽  
Author(s):  
Patricia G. Llana
Keyword(s):  
Initial Energy ◽  
Performance Standard ◽  
Initial Kinetic Energy ◽  
Federal Regulations ◽  
Finite Element Analyses ◽  
European Standard ◽  
Safety Program ◽  
Equipment Safety ◽  
Grade Crossing ◽  
The Impact

In support of the Federal Railroad Administration’s (FRA) Railroad Equipment Safety Program, American and European grade-crossing collision scenarios were evaluated and compared. Finite element analyses (FEA) were employed to subject an FRA-compliant passenger car to grade-crossing collision scenarios defined in both the proposed FRA Code of Federal Regulations (CFR) and European Standard (EN) 15227. The proposed FRA collision scenario involved a single car impacted by a cart. The cart had a punch mounted to it to hit a specific post of the end frame of the car. The EN 15227 collision scenario involved a complete train consist impacting a large deformable obstacle that approximates a lorry. The analyses show that these collision scenarios, while both grade-crossing scenarios, are very different not only in terms of the impact object and the amount of initial kinetic energy involved, but also in terms of how the car is loaded and deformed during impact. The FRA scenario is shown to be easier to analyze as well as easier to test than the EN 15227 scenario. Additionally, the FRA scenario is safer to test because of the levels of initial energy involved. The FRA scenario also provides clearer metrics of success. The FRA-compliant car utilized in the analyses and test conducted for this paper passed both FRA and EN 15227 grade-crossing collision scenarios according to the requirements for each respective standard. However, the analyses show that despite both scenarios providing for energy absorption in a grade-crossing collision, because the manner in which the car is loaded and deformed (concentrated vs. distributed) is different, the FRA performance standard and EN 15227 grade-crossing collision scenarios are not equivalent and mutual compliance is not guaranteed.

Impact Load Buffering Method Based on Stress Wave Attenuation Principle

2019 ◽  
Vol 11 (02) ◽  
pp. 1950019 ◽  
Author(s):  
Lin Gan ◽  
He Zhang ◽  
Cheng Zhou ◽  
Lin Liu
Keyword(s):  
Stress Wave ◽  
Wave Attenuation ◽  
Impact Load ◽  
Dynamics Simulation ◽  
Scanning System ◽  
Isolation Method ◽  
Element Analysis ◽  
System A ◽  
High Emission ◽  
The Impact

Rotating scanning motor is the important component of synchronous scanning laser fuze. High emission overload environment in the conventional ammunition has a serious impact on the reliability of the motor. Based on the theory that the buffer pad can attenuate the impact stress wave, a new motor buffering Isolation Method is proposed. The dynamical model of the new buffering isolation structure is established by ANSYS infinite element analysis software to do the nonlinear impact dynamics simulation of rotating scanning motor. The effectiveness of Buffering Isolation using different materials is comparatively analyzed. Finally, the Macht hammer impact experiment is done, the results show that in the experience of the 70,000[Formula: see text]g impact acceleration, the new buffering Isolation method can reduce the impact load about 15 times, which can effectively alleviate the plastic deformation of rotational scanning motor and improve the reliability of synchronization scanning system. A new method and theoretical basis of anti-high overload research for Laser Fuze is presented.

scholarly journals Comparison of Industrial Quenching Oils

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 250
Author(s):  
Jiří Hájek ◽  
Zaneta Dlouha ◽  
Vojtěch Průcha
Keyword(s):  
State Of The Art ◽  
Cooling Capacity ◽  
Steel Grade ◽  
Cooling Curves ◽  
Cooling Process ◽  
Industrial Practice ◽  
Product Size ◽  
Cct Curve ◽  
Hardening Power ◽  
The Impact

This article is a response to the state of the art in monitoring the cooling capacity of quenching oils in industrial practice. Very often, a hardening shop requires a report with data on the cooling process for a particular quenching oil. However, the interpretation of the data can be rather difficult. The main goal of our work was to compare various criteria used for evaluating quenching oils. Those of which prove essential for operation in tempering plants would then be introduced into practice. Furthermore, the article describes monitoring the changes in the properties of a quenching oil used in a hardening shop, the effects of quenching oil temperature on its cooling capacity and the impact of the water content on certain cooling parameters of selected oils. Cooling curves were measured (including cooling rates and the time to reach relevant temperatures) according to ISO 9950. The hardening power of the oil and the area below the cooling rate curve as a function of temperature (amount of heat removed in the nose region of the Continuous cooling transformation - CCT curve) were calculated. V-values based on the work of Tamura, reflecting the steel type and its CCT curve, were calculated as well. All the data were compared against the hardness and microstructure on a section through a cylinder made of EN C35 steel cooled in the particular oil. Based on the results, criteria are recommended for assessing the suitability of a quenching oil for a specific steel grade and product size. The quenching oils used in the experiment were Houghto Quench C120, Paramo TK 22, Paramo TK 46, CS Noro MO 46 and Durixol W72.

scholarly journals A Rational Numerical Method for Simulation of Drop-Impact Dynamics of Oleo-Pneumatic Landing Gear

2021 ◽  
Vol 11 (9) ◽  
pp. 4136
Author(s):  
Rosario Pecora
Keyword(s):  
Numerical Method ◽  
Initial Conditions ◽  
Impact Load ◽  
Numerical Models ◽  
Landing Gear ◽  
Design Stage ◽  
Impact Dynamics ◽  
State Variables ◽  
Adopted Model ◽  
The Impact

Oleo-pneumatic landing gear is a complex mechanical system conceived to efficiently absorb and dissipate an aircraft’s kinetic energy at touchdown, thus reducing the impact load and acceleration transmitted to the airframe. Due to its significant influence on ground loads, this system is generally designed in parallel with the main structural components of the aircraft, such as the fuselage and wings. Robust numerical models for simulating landing gear impact dynamics are essential from the preliminary design stage in order to properly assess aircraft configuration and structural arrangements. Finite element (FE) analysis is a viable solution for supporting the design. However, regarding the oleo-pneumatic struts, FE-based simulation may become unpractical, since detailed models are required to obtain reliable results. Moreover, FE models could not be very versatile for accommodating the many design updates that usually occur at the beginning of the landing gear project or during the layout optimization process. In this work, a numerical method for simulating oleo-pneumatic landing gear drop dynamics is presented. To effectively support both the preliminary and advanced design of landing gear units, the proposed simulation approach rationally balances the level of sophistication of the adopted model with the need for accurate results. Although based on a formulation assuming only four state variables for the description of landing gear dynamics, the approach successfully accounts for all the relevant forces that arise during the drop and their influence on landing gear motion. A set of intercommunicating routines was implemented in MATLAB® environment to integrate the dynamic impact equations, starting from user-defined initial conditions and general parameters related to the geometric and structural configuration of the landing gear. The tool was then used to simulate a drop test of a reference landing gear, and the obtained results were successfully validated against available experimental data.

scholarly journals Smoothing additive manufactured parts using ns-pulsed laser radiation

2021 ◽  
Author(s):  
Florian Kuisat ◽  
Fernando Lasagni ◽  
Andrés Fabián Lasagni
Keyword(s):  
Surface Roughness ◽  
Mechanical Performance ◽  
State Of The Art ◽  
Pulsed Laser ◽  
Industrial Applications ◽  
Laser Source ◽  
Pulsed Laser Radiation ◽  
Current State ◽  
The Impact

AbstractIt is well known that the surface topography of a part can affect its mechanical performance, which is typical in additive manufacturing. In this context, we report about the surface modification of additive manufactured components made of Titanium 64 (Ti64) and Scalmalloy®, using a pulsed laser, with the aim of reducing their surface roughness. In our experiments, a nanosecond-pulsed infrared laser source with variable pulse durations between 8 and 200 ns was applied. The impact of varying a large number of parameters on the surface quality of the smoothed areas was investigated. The results demonstrated a reduction of surface roughness Sa by more than 80% for Titanium 64 and by 65% for Scalmalloy® samples. This allows to extend the applicability of additive manufactured components beyond the current state of the art and break new ground for the application in various industrial applications such as in aerospace.

scholarly journals Analysis on Force Transmission Characteristics of Two-Legged Shield Support under Impact Loading

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Qing-liang Zeng ◽  
Zhao-sheng Meng ◽  
Li-rong Wan ◽  
Cheng-long Wang
Keyword(s):  
Structural Design ◽  
Load Transfer ◽  
Impact Load ◽  
Force Transmission ◽  
Full Account ◽  
Flexible Bodies ◽  
Powered Support ◽  
Structural Design Optimization ◽  
Hinge Points ◽  
The Impact

To study the load transfer characteristics of a two-legged shield powered support, a numerical simulation model of the support was established using the multibody dynamics software ADAMS. The model took full account of the hydraulic-elastic deformation characteristics of the support, as a series spring-damper system was used to replace the leg and the equilibrium jack. The canopy, goaf shield, lemniscate bars, and equilibrium jack are equivalent to flexible bodies. The setting force of the leg was provided by the preload of the equivalent spring, the static roof load was simulated using a slope signal, and the impact load was simulated using a step signal. Using the model, the impact and excitation effects of each hinge joint of the support were analyzed under different impact load conditions across the canopy. The results show that the location of the impact load affects the force transmissions of all hinge points of the support. Both the impact effect and the excitation effect are at a minimum when the impact force is located near the leg action line. These results are useful for the adaptive control and structural design optimization of the support.

scholarly journals Cash Flow Bullwhip—Literature Review and Research Perspectives

Logistics ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 8
Author(s):  
Hicham Lamzaouek ◽  
Hicham Drissi ◽  
Naima El Haoud
Keyword(s):  
Literature Review ◽  
Customer Service ◽  
Cash Flow ◽  
State Of The Art ◽  
Research Work ◽  
Bullwhip Effect ◽  
Research Perspectives ◽  
Financial Perspective ◽  
The Impact ◽  
Exhaustive List

The bullwhip effect is a pervasive phenomenon in all supply chains causing excessive inventory, delivery delays, deterioration of customer service, and high costs. Some researchers have studied this phenomenon from a financial perspective by shedding light on the phenomenon of cash flow bullwhip (CFB). The objective of this article is to provide the state of the art in relation to research work on CFB. Our ambition is not to make an exhaustive list, but to synthesize the main contributions, to enable us to identify other interesting research perspectives. In this regard, certain lines of research remain insufficiently explored, such as the role that supply chain digitization could play in controlling CFB, the impact of CFB on the profitability of companies, or the impacts of the omnichannel commerce on CFB.

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