Design, Construction, and Analysis of Pavements Using Accelerated Loading Facility

1997 ◽  
Vol 1590 (1) ◽  
pp. 73-79
Author(s):  
Freddy L. Roberts ◽  
Louay N. Mohammad ◽  
Ludfi Djakfar ◽  
Amar Raghavendra
Keyword(s):  
Fatigue Cracking ◽  
Primary Response ◽  
Performance Data ◽  
Test Facility ◽  
Response Analysis ◽  
Damage Prediction ◽  
Testing Facility ◽  
Short Period ◽  
Transportation Research ◽  
Design Construction

The Louisiana Transportation Research Center has recently completed the construction of a full-scale pavement test facility using the accelerated loading facility (ALF) machine. This facility contains nine pavement test sections, 12-m (38-ft) long and 3.66-m (12-ft) wide that are loaded by the ALF machine with loads ranging from 34.71 to 111.25 kN (7,800 to 25,000 lbf) on a dual-tire assembly. The advantage of this testing facility is its ability to cause a pavement to fail in a short period of time. In addition, the data acquisition methods and instrumentation used in this testing facility allow researchers to obtain reliable and representative performance data. The first test section has been loaded to failure and a preliminary analysis of the data is completed. VESYS 3A-M, a microcomputer version of the VESYS series, has been selected for the analysis due to its ability to predict damage and its flexibility. The analysis consists of the primary response analysis to determine strains, stresses, and deflection of the pavement and damage-prediction modeling that includes rutting, fatigue cracking, and roughness. The analysis was conducted by comparing the data obtained from field with that predicted by VESYS 3A-M. The performance data obtained from the field include fatigue cracking, rutting, and roughness. The analysis showed that VESYS 3A-M outputs are in good agreement with those obtained from the field.

Frequency Response Analysis of Piecewise Nonlinear Vibration Isolator

2005 ◽  
Author(s):  
Patrick Stahl ◽  
G. Nakhaie Jazar
Keyword(s):  
Low Frequency ◽  
High Amplitude ◽  
Relative Displacement ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
State Behavior ◽  
Vibration Isolators ◽  
Short Period ◽  
Secondary Suspension ◽  
Low Amplitude

Non-smooth piecewise functional isolators are smart passive vibration isolators that can provide effective isolation for high frequency/low amplitude excitation by introducing a soft primary suspension, and by preventing a high relative displacement in low frequency/high amplitude excitation by introducing a relatively damped secondary suspension. In this investigation a linear secondary suspension is attached to a nonlinear primary suspension. The primary is assumed to be nonlinear to model the inherent nonlinearities involved in real suspensions. However, the secondary suspension comes into action only during a short period of time, and in mall domain around resonance. Therefore, a linear assumption for the secondary suspension is reasonable. The dynamic behavior of the system subject to a harmonic base excitation has been analyzed utilizing the analytic results derived by applying the averaging method. The analytic results match very well in the transition between the two suspensions. A sensitivity analysis has shown the effect of varying dynamic parameters in the steady state behavior of the system.

scholarly journals Flame response to high-frequency oscillations in a cryogenic oxygen/hydrogen rocket combustor

2019 ◽  
Author(s):  
N. Fdida ◽  
J. Hardi ◽  
H. Kawashima ◽  
B. Knapp ◽  
M. Oschwald ◽  
...  
Keyword(s):  
High Frequency ◽  
Acoustic Resonance ◽  
High Amplitude ◽  
Operating Conditions ◽  
Test Facility ◽  
Response Analysis ◽  
Rocket Engines ◽  
Acoustic Oscillations ◽  
Spatially Resolved ◽  
Flame Response

Experiments presented in this paper were conducted with the BKH rocket combustor at the European Research and Technology Test Facility P8, located at DLR Lampoldshausen. This combustor is dedicated to study the effects of high magnitude instabilities on oxygen/hydrogen flames, created by forcing high-frequency (HF) acoustic resonance of the combustion chamber. This work addresses the need for highly temporally and spatially resolved visualization data, in operating conditions representative of real rocket engines, to better understand the flame response to high amplitude acoustic oscillations. By combining ONERA and DLR materials and techniques, the optical setup of this experiment has been improved to enhance the existing database with more highly resolved OH* imaging to allow detailed response analysis of the flame. OH* imaging is complemented with simultaneous visible imaging and compared to each other here for their ability to capture flame dynamics.

Development of Advanced Mechanical System for 3-D Full-Scale Earthquake Testing Facility

2002 ◽  
Author(s):  
Shintaro Watanabe ◽  
Kazuhiko Maekawa ◽  
Yasuyuki Tanaka ◽  
Akesi Koike ◽  
Yukiharu Yamasaki
Keyword(s):  
Full Scale ◽  
Shaking Table ◽  
Test Facility ◽  
Wave Form ◽  
Low Friction ◽  
3 Dimensional ◽  
Large Size ◽  
Testing Facility ◽  
Ring Seal ◽  
Hyogo Prefecture

The largest 3-dimensional vibration test facility is being constructed in Japan’s Hyogo Prefecture. The objective of this facility is to assist the investigation on the process of the collapsing phenomena of a full-scale structure in an earthquake. This facility has a large size shaking table (15 m × 20 m), with a payload of 12 MN. Actuators are connected to the shaking table via 3-D links. In order to reduce the distortion of accelaration wave form, low friction tribo-elements are employed in the actuators; a hydrostatic bearing for rod supports, a pressure balanced seal for pistons, a floating ring seal for 3-dimensional joints. Since these elements are large and heavily loaded, the deformation of them are relatively large compared to the oil film gap in the elements and make design difficult. The paper exhibits the tribological performance of the actuators and joints.

Correlation of Superpave G*/Sin δ with Rutting Test Results from Accelerated Loading Facility

1998 ◽  
Vol 1630 (1) ◽  
pp. 53-61 ◽  
Author(s):  
James A. Sherwood ◽  
Nathaniel L. Thomas ◽  
Xicheng Qi
Keyword(s):  
Data Analysis ◽  
Predictive Models ◽  
Laboratory Tests ◽  
Fatigue Cracking ◽  
Full Scale ◽  
Test Results ◽  
Testing Facility ◽  
Pavement Testing ◽  
Analysis System ◽  
Highway Research

In 1992, FHWA initiated a Superpave validation study by utilizing the Accelerated Loading Facility (ALF) at the Turner-Fairbank Highway Research Center in McLean, Virginia. The study focused on the validation of the concepts, tests, and predictive models underlying the Superpave binder specifications and mixture analysis system. Twelve full-scale pavement lanes with 48 test sites were constructed at the FHWA Pavement Testing Facility in 1993. Pavement testing with the ALF started in late spring of 1994. The results of accelerated full-scale pavement tests in conjunction with extensive laboratory tests will be used to validate the Superpave binder parameters for rutting and fatigue cracking. Presented in this paper are the results of rutting tests and some of the data analysis completed through June 1997.

Seismic design spectra for different soil classes

2013 ◽  
Vol 46 (2) ◽  
pp. 79-87 ◽  
Author(s):  
Rajesh P. Dhakal ◽  
Sheng-Lin Lin ◽  
Alexander K. Loye ◽  
Scott J. Evans
Keyword(s):  
Seismic Design ◽  
Soft Soil ◽  
Response Analysis ◽  
Seismic Demand ◽  
Analysis Tool ◽  
Spectral Acceleration ◽  
Acceleration Response ◽  
Design Spectra ◽  
Nonlinear Site Response ◽  
Short Period

This paper investigates the validity of the soil class dependent spectral shape factors used to calculate seismic design actions in the New Zealand seismic design standard NZS1170.5, which currently specifies seismic design spectra corresponding to five different soil classes. According to the current provisions stipulated in NZS1170.5, for all natural periods, the seismic demand for structures on soft soil is either equal to or greater than that for structures on hard soil. This is opposite to the basic structural dynamics theory which suggests that an increase in stiffness of a system results in an increase in the acceleration response. In this pretext, a numerical parametric study is undertaken using a nonlinear site response analysis tool in order to capture the effect of soil characteristics on structural seismic demand and to scrutinize the validity of the current site specific seismic design spectra. It is identified that the level of input ground motion intensity and shear stiffness of the soil deposit (represented by its shear wave velocity Vs) greatly affect the maximum acceleration and frequency content of the surface motion. The study found some shortfalls in the way the current code defines seismic design demand, in particular the hierarchy of soil stiffness at low structural periods. It was found that stiff soils generally tend to have a higher spectral acceleration response in comparison to soft soils although this trend is less prominent for high intensity bed rock motions. It was also found that for medium to hard soils the spectral acceleration response at short period is grossly underestimated by the current NZS1170.5 provisions. Based on the outcomes of the parametric numerical analyses, a revised strategy to determine structural seismic demand for different soil classes is proposed and its application is demonstrated through an example.

Performance Prediction of Louisiana Accelerated Loading Facility Test Sections

2000 ◽  
Vol 1716 (1) ◽  
pp. 108-115
Author(s):  
Ludfi Djakfar ◽  
Freddy L. Roberts
Keyword(s):  
Performance Prediction ◽  
Field Performance ◽  
Fatigue Cracking ◽  
Surface Cracking ◽  
Unbound Granular Materials ◽  
Soil Cement ◽  
Different Types ◽  
Reasonable Prediction ◽  
Transportation Research ◽  
Unbound Granular Material

Using the accelerated loading facility (ALF), the Louisiana Transportation Research Center recently conducted an accelerated pavement test of nine test sections that consisted of the same asphalt wearing course but had different types and thicknesses of crushed stone and soil cement bases and subbases. One of the aims of the project was to compare observed field performance with that predicted with use of the VESYS 3A-M mechanistic prediction model, which predicts the development of rutting, cracking, and roughness, along with serviceability [present serviceability index (PSI)] over time. It was found that VESYS provided a reasonable prediction of observed rutting and PSI—albeit an underestimation—but a poor estimate of surface cracking. This was probably related to the fact that the observed cracking was due to shrinkage of the soil cement rather than fatigue cracking under the load, and also to the fact that VESYS is generally used to model unbound granular materials that have a modulus no greater than 690 MPa (100 ksi). The modulus of soil cement material tested by ALF was 105 MPa (150 ksi) and its behavior under load would be different from that of an unbound granular material. More research is needed into the behavior of soil cement bases, their influence on the cracking of asphalt surfacings, and the most appropriate input into VESYS to model this behavior.

Lessons learnt during the design, construction and start-up phase of a molten salt testing facility

2014 ◽  
Vol 62 (2) ◽  
pp. 520-528 ◽  
Author(s):  
Margarita-Manuela Rodríguez-García ◽  
Miguel Herrador-Moreno ◽  
Eduardo Zarza Moya
Keyword(s):  
Molten Salt ◽  
Lessons Learnt ◽  
Start Up ◽  
Testing Facility ◽  
Design Construction

Design, construction and performance of the current lead test facility CuLTKa

Cryogenics ◽  
2017 ◽  
Vol 86 ◽  
pp. 22-29 ◽  
Author(s):  
T. Richter ◽  
S. Bobien ◽  
W.H. Fietz ◽  
M. Heiduk ◽  
R. Heller ◽  
...  
Keyword(s):  
Current Lead ◽  
Test Facility ◽  
And Performance ◽  
Design Construction

Concepts and Techniques for Helicopter Airframe Fatigue Tests

1966 ◽  
Vol 11 (3) ◽  
pp. 45-57 ◽  
Author(s):  
Walter A. Lane
Keyword(s):  
Experimental Design ◽  
Fatigue Test ◽  
Structural Integrity ◽  
Fatigue Cracking ◽  
Fatigue Tests ◽  
Test Facility ◽  
Test Results ◽  
Fail Safe ◽  
Inspection Techniques ◽  
Automatic Simulation

Between February 1961 and June 1963, Sikorsky Aircraft, under the sponsorship of the U. S. Navy Bureau of Naval Weapons, performed the first laboratory fatigue test of a full scale helicopter airframe. This paper presents the concepts and techniques developed by Sikorsky for such tests. Airframe fatigue test concepts are directed toward defining modes of fatigue cracking, measuring rates of crack propagation, and demonstrating the adequacy of recommended inspection techniques and intervals to provide “fail safe” structural integrity. The experimental design includes consideration of the test article configuration, acceleration of test loads, loading spectra, and evaluation of test fractures. The design of the SH‐3A airframe fatigue test facility to provide automatic simulation of flight and landing loads, and the development problems encountered in achieving this capability are described. The facility and techniques to be used for CH‐53A airframe fatigue tests reflect improvements resulting from SH‐3A test experience. Correlation of airframe fatigue test results and service experience demonstrates the validity of the test concepts and techniques as well as the “fail safe” characteristics of the SH‐3A airframe.

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