scholarly journals Dynamic ROPS Test for Tractors over 6,000 Kilograms

2018 ◽  
Vol 61 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Caleb M. Lindhorst ◽  
Roger M. Hoy ◽  
Santosh K. Pitla ◽  
Michael F. Kocher
Keyword(s):  
Dynamic Testing ◽  
Dynamic Test ◽  
Strength Properties ◽  
Technical Note ◽  
Test Method ◽  
Cold Weather ◽  
Drop Height ◽  
Static Tests ◽  
Static Test ◽  
Protective Structures

Abstract. OECD static tests (Codes 4, 6, 7, and 8) for agricultural rollover protective structures (ROPS) have become accepted standards for evaluating the ability of these structures to protect the operator during tractor rollover events. The strength properties of some materials typically used in ROPS change because of cold weather embrittlement at low temperatures. The static ROPS tests lack the ability to evaluate the strength of these structures during cold weather. The use of the dynamic ROPS test is well noted as a means for proving cold weather embrittlement resistance properties. Unfortunately, application of the OECD dynamic ROPS test (Code 3) is restricted to tractors with unballasted mass greater than 600 kg and generally less than 6,000 kg. The analyses presented in this technical note were undertaken to evaluate the extension of the OECD Code 3 dynamic ROPS test to tractors with unballasted mass of 6,000 kg or more. Tractor unballasted mass and wheelbase data from 47 wheeled tractors tested at the Nebraska Tractor Test Lab from 2014 to 2016 were used to explore the possibility of using a dynamic test method for evaluating the ability of ROPS on tractors with unballasted mass greater than 6,000 kg to meet the safety requirements of agricultural tractor ROPS. The data were graphed and analyzed to determine the required pendulum drop height and energy values to be applied to the ROPS by extending the existing equations to tractors over 6,000 kg. For tractors over 6,000 kg mass, it was determined that pendulum drop heights were too great for practical use. Three pendulum masses were proposed for the dynamic ROPS test: a 2,000 kg pendulum for tractors with mass less than 7,000 kg, a 4,000 kg pendulum for tractors with mass of 7,000 kg or more and less than 14,000 kg, and a 6,000 kg pendulum for tractors with mass of 14,000 kg or more and less than 23,000 kg. Alternate equations were developed for the drop height of each pendulum to meet the energy requirements that are expected to provide similar permanent deflections as those obtained when using the static ROPS test when considering the effect of strain rates on material properties. Tests should be conducted to determine how the results (permanent deflections) from the proposed dynamic ROPS test compare with results from the accepted static ROPS tests. It is further proposed that dynamic testing be conducted with the tractor rigidly restrained in a manner similar to the static test to better account for the wide variety of available tires and mountings for each tractor model. Keywords: Energy, Impact test, Pendulum, Reference mass, ROPS, Tractors.

The structural characteristics of microengineered bridges

2000 ◽  
Vol 214 (2) ◽  
pp. 351-357
Author(s):  
J S Burdess ◽  
A J Harris ◽  
D Wood ◽  
R Pitcher
Keyword(s):  
Internal Stress ◽  
Young’S Modulus ◽  
Dynamic Testing ◽  
Young's Modulus ◽  
Structural Characteristics ◽  
Dynamic Test ◽  
Test Method ◽  
Laser Vibrometer ◽  
Test Procedures ◽  
Static Tests

The paper considers the measurement of Young's modulus and internal stress in micro-engineered bridge structures. Values determined from the results of static tests, obtained from the measurement of compliance using a nanoindenter, are compared with values derived from natural frequency measurements obtained from dynamic testing using a laser vibrometer. Both test procedures use mathematical models ‘fitted’ to experimental data to estimate Young's modulus and internal stress. For the case of boron-doped silicon bridges the dynamic test method is shown to produce the superior estimates.

scholarly journals Development and Fabrication of State-of-the-Art End Structures for Budd M1 Cars

2008 ◽  
Author(s):  
Richard Stringfellow ◽  
Christopher Paetsch ◽  
Gabriel Amar
Keyword(s):  
Energy Absorption ◽  
Public Transportation ◽  
Dynamic Test ◽  
Test Method ◽  
Detailed Design ◽  
Static Tests ◽  
Car Body ◽  
Fea Model ◽  
Final Design ◽  
Active Research

The Volpe Center and the Federal Railroad Administration are engaged in active research aimed at improving rail vehicle crashworthiness. One component of this research is focused on improving the performance of passenger train cab cars during collisions with heavy objects at grade crossings. New standards have been approved by the American Public Transportation Association that increase the strength requirements for cab car end structures and impose further requirements on their ability to absorb energy during a collision. The FRA has issued a notice of proposed rulemaking (NPRM) to include these new standards in 49CFR238.211. These standards include requirements for demonstration of energy absorption through either quasi-static or dynamic tests. The intent of each test method is to demonstrate a minimum level of energy absorption—120,000 ft-lbs for a corner post load and 135,000 ft-lbs for a collision post load—while limiting occupied volume intrusion to less than 10 inches. To aid in the development of these new standards, the FRA and Volpe Center are conducting a set of three tests: quasi-static loading of both the collision and corner posts, and dynamic loading of the collision post only. (A dynamic test of the corner post was conducted as part of an earlier program). These tests were developed to illustrate testing methodologies and to demonstrate the feasibility of the new energy absorption and large deformation requirements. In+ each test, the post is loaded 30 inches above the underframe by a proxy object that is 36-inches wide, with a 48-inch diameter cylindrical face. In support of this testing program, the research reported here focused on the design and fabrication of end frames suitable for retrofitting onto the cab end of a Budd M1 cab car. The design of an end frame for retrofit onto the cab end of a Budd Pioneer cab car was modified to account for differences between the two car designs. In addition, reinforcements to the M1 car body and connections from the end frame to the car body were designed and fabricated. An FEA model of the end frame retrofit onto the M1 cab car was developed based upon the detailed design. A series of linear and nonlinear static, quasi-static, and dynamic FEAs were performed to evaluate the performance of the design. Preliminary analyses revealed the need for a few minor modifications to the connections in order to meet design requirements; these were incorporated into the final design for manufacture. Components for the end frame, connections between the end frame and the car body, and reinforcements to the car body were fabricated based on detailed design drawings and then assembled and connected to the reinforced M1 Car, from which the original end frame had been cut off. A successful dynamic test was completed in April, 2008; quasi-static tests are scheduled for summer 2008. The results of FEA model predictions are compared with the results of the dynamic test.

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 Fixing Efficiency Values by Unfixing Compressor Speed: Dynamic Test Method for Heat Pumps

2019 ◽  
Author(s):  
Carsten Palkowski ◽  
Andreas Zottl ◽  
Ivan Malenkovic ◽  
Anne Simo
Keyword(s):  
Dynamic Behavior ◽  
Heat Pump ◽  
Performance Test ◽  
Dynamic Testing ◽  
Dynamic Test ◽  
Electricity Consumption ◽  
Heat Pumps ◽  
Test Method ◽  
Temperature Changes ◽  
Seasonal Performance

The growing market penetration of heat pumps indicates the need for a performance test method which better reflects the dynamic behavior of heat pumps. In this contribution, we developed and implemented a dynamic test method for the evaluation of the seasonal performance of heat pumps by means of laboratory testing. Current standards force the heat pump control inactive by fixing the compressor speed. In contrast, during dynamic testing, the compressor runs unfixed while the heat pump is subjected to a temperature profile. The profile consists of the different outdoor temperatures of a typical heating season based on the average European climate and also includes temperature changes to reflect the dynamic behavior of the heat pump. The seasonal performance can be directly obtained from the measured heating energy and electricity consumption making subsequent data interpolation and recalculation with correction factors obsolete. The method delivers results with high precision and high reproducibility and could be an appropriate method for a fair rating of heat pumps.

scholarly journals Fixing Efficiency Values by Unfixing Compressor Speed: Dynamic Test Method for Heat Pumps

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1045 ◽  
Author(s):  
Carsten Palkowski ◽  
Andreas Zottl ◽  
Ivan Malenkovic ◽  
Anne Simo
Keyword(s):  
Dynamic Behavior ◽  
Heat Pump ◽  
Performance Test ◽  
Dynamic Testing ◽  
Dynamic Test ◽  
Electricity Consumption ◽  
Heat Pumps ◽  
Test Method ◽  
Temperature Changes ◽  
Seasonal Performance

The growing market penetration of heat pumps indicates the need for a performance test method that better reflects the dynamic behavior of heat pumps. In this contribution, we developed and implemented a dynamic test method for the evaluation of the seasonal performance of heat pumps by means of laboratory testing. Current standards force the heat pump control inactive by fixing the compressor speed. In contrast, during dynamic testing, the compressor runs unfixed while the heat pump is subjected to a temperature profile. The profile consists of the different outdoor temperatures of a typical heating season based on the average European climate and also includes temperature changes to reflect the dynamic behavior of the heat pump. The seasonal performance can be directly obtained from the measured heating energy and electricity consumption making subsequent data interpolation and recalculation with correction factors obsolete. The method delivers results with high precision and high reproducibility and could be an appropriate method for a fair rating of heat pumps.

scholarly journals Dynamic testing to determine and predict trampoline function

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
Olivia H. Brown ◽  
David R. Mullineaux ◽  
Francis Mulloy
Keyword(s):  
Injury Risk ◽  
Dynamic Testing ◽  
Dynamic Test ◽  
Rate Of Change ◽  
Test Method ◽  
Load Testing ◽  
Safety Standards ◽  
Bed Deformation ◽  
Explained Variance ◽  
Spring Constants

AbstractSafety standards for domestic trampolines are based on static-load testing using a factor of five times the maximum intended user mass. This paper presents a dynamic test method for trampolines, and provides measures of the users’ performance (e.g., peak acceleration, Accmax) and injury risk (e.g., mean rate of change of acceleration, Jerkmean). Uniform masses (41–116 kg) were dropped from 0.66 m onto the bed centre of nineteen different trampolines. Trampoline bed and spring stretches, mass flight time (FlightT) and accelerations were recorded using motion capture and accelerometers. Thirty-seven percent of trampolines exceeded the static safety standard bed deformation limits (80% of frame height) by 11 ± 6% with dynamic testing (mean ± standard deviation). Across all trampolines and masses dropped, the Accmax ranged from 5.1 to 7.6 g, suggesting the factor of five used in static-loading safety standards needs reviewing. Statistically significant negative correlations (p < 0.05) were found between trampoline bed diameter and Accmax (r =  – 0.88), Jerkmean (r =  – 0.77) and FlightT (r =  – 0.82). Furthermore, significant correlations (p < 0.05) were also found between the mass dropped and Accmax (r =  – 0.27), Jerkmean (r =  – 0.59) and FlightT (r = 0.25). The combined effects of the spring constants, number of springs, bed diameters and masses dropped were described in predictive multivariate equations for Accmax (explained variance, R2 = 95%) and maximum vertical bed deformation (R2 = 85%). These findings from dynamic testing may assist manufacturers in designing trampolines that meet safety standards while maximising user performance and reducing injury risk.

A robotic chewing simulator supplying six-axis mandibular motion, high occlusal force, and a saliva environment for denture tests

2021 ◽  
pp. 095441192110056
Author(s):  
Wenlong Qin ◽  
Ming Cong ◽  
Dong Liu ◽  
Xiang Ren
Keyword(s):  
Flow Rate ◽  
Failure Modes ◽  
Testing Machine ◽  
Dynamic Test ◽  
Dynamic Tests ◽  
Occlusal Force ◽  
Static Tests ◽  
Static Test ◽  
Axis Parallel

Six-axis motion is essential for the evaluation of the wear failure modes of dental prostheses with complete teeth morphologies, and a high occlusal force capacity is vital for static clenching and dynamic bruxism. Additionally, the saliva environment influences abrasive particles and crack growth. The present research was aimed at the development of a six-axis masticatory and saliva simulator with these capacities. The masticatory simulator was designed based on a six-axis parallel mechanism, and the saliva simulator consisted of a saliva circuit and a temperature control loop. A control system of the masticatory and saliva simulators was constructed. The operating interface includes a centric occlusal position search, a static test, a dynamic test, a saliva supply, and data reporting. The motion and force performances of the masticatory simulator were evaluated. The flow rate and temperature change of the saliva simulator were calculated. For the occlusal position-searching, the driving amplitude is linear with the moving variables during minor one-axis motion. For the static tests, the force capacity of the driving chain is 3540 N, while for the dynamic tests, the force capacity is 1390 N. The flow rate of the saliva is 0.18–51.84 mL/min, and the saliva can effectively wet the prosthesis without the risk of overflow. Moreover, the saliva temperature can increase from room temperature (23°C) to body temperature (37°C) in about 6 min. The proposed DUT-2 simulator with six-axis motion, high force, and a salvia environment provides an in vitro testing approach to validate numerical simulation results and explain the clinical failure modes of prostheses. The centric occlusal position-searching, static tests, and dynamic tests could therefore be executed using a single testing machine. Moreover, the proposed device is more compact than previously reported six-axis masticatory simulators, including the Bristol simulator and DUT-1 simulator.

Sign in / Sign up

Export Citation Format

Share Document