Pilot and Observer Performance in Simulated Low Altitude High Speed Flight

1965 ◽  
Vol 7 (3) ◽  
pp. 257-265 ◽  
Author(s):  
Ben Schohan ◽  
Harve E. Rawson ◽  
Stanley M. Soliday
Keyword(s):  
Atmospheric Turbulence ◽  
High Speed ◽  
Target Identification ◽  
Observer Performance ◽  
Acceleration Time ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Low Altitude ◽  
Vertical Accelerations

Responses of experienced pilots and aerial observers were studied in simulated low-altitude, high-speed (LAHS) flight. The pilots “flew” three-hour surveillance missions at airspeeds of .4M and .9M in different degrees of simulated atmospheric turbulence. Flying ability decreased from .4 to .9M; however, intensity of vertical accelerations did not seem to affect flying ability except at the most severe levels. Target identification was unimpaired by either turbulence or airspeed. The observers also flew three-hour missions while experiencing acceleration time histories recorded from the pilot's flights. Target identification deteriorated as airspeed increased from 0.4 to 0.9 Mach. Gust intensity did not affect performance of any of their tasks. Performance efficiency on all tasks did not deteriorate from beginning to end of the missions of both pilots and observers.

Metrics for the Comparison of Acceleration Time Histories

2017 ◽  
Author(s):  
Nithyagopal Goswami ◽  
Mourad Zeghal ◽  
Majid Manzari ◽  
Bruce Kutter
Keyword(s):  
Acceleration Time ◽  
Acceleration Time Histories ◽  
Time Histories

Selection and Scaling Time History Records for Performance-Based Design

2017 ◽  
pp. 1-35
Author(s):  
Yasin M. Fahjan ◽  
F. İlknur Kara ◽  
Aydın Mert
Keyword(s):  
Ground Motion ◽  
Strong Ground Motion ◽  
Time History ◽  
Design Code ◽  
Uniform Hazard Spectra ◽  
Acceleration Time ◽  
Acceleration Time Histories ◽  
Recent Developments ◽  
Time Histories ◽  
Strong Ground

Recent developments in performance-based analyses and the high performance of computational facilities have led to an increased trend for utilizing nonlinear time-history analysis in seismic evaluation of the performance of structures. One of the crucial issues of such analysis is the selection of appropriate acceleration time histories set that satisfy design code requirements at a specific site. In literature, there are three sources of acceleration time histories: 1) recorded accelerograms in real earthquakes scaled to match design code spectrum/uniform hazard spectra/conditional mean spectrum, 2) artificial records generated from white noise spectra to satisfy design code spectrum, and 3) synthetic records obtained from seismological models. Due to the increase of available strong ground motion database, using and scaling real recorded accelerograms is becoming one of the most contemporary research issues in this field. In this study, basic methodologies and criteria for selecting strong ground motion time histories are discussed. Design code requirements for scaling are summarized for ASCE/SEI-7-10, EC8 and Turkish Seismic Codes. Examples for scaling earthquake records to uniform hazard spectra are provided.

scholarly journals Development of two components acceleration time histories for Semarang, Indonesia, due to Semarang fault earthquake scenarios using 30 meters soil deposit model

2018 ◽  
Vol 159 ◽  
pp. 01043
Author(s):  
Windu Partono
Keyword(s):  
Site Response ◽  
Historical Earthquakes ◽  
Structure Design ◽  
Site Response Analysis ◽  
Response Analysis ◽  
Acceleration Time ◽  
Earthquake Scenarios ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Deposit Model

Development of surface acceleration time histories is important for dynamic analysis of structure design and evaluation. Acceleration time histories usually developed from seismograph records due to specific earthquake event. Following the research conducted by Team for Revision of Seismic Hazard Maps of Indonesia 2010 and 2016, Lasem fault and Semarang fault are two closest and dangerous shallow crustal fault earthquake sources which must be taken into account for seismic mitigation of Semarang. This paper presents the development two components surface acceleration time histories for Semarang caused by Semarang fault earthquake scenarios, with magnitude from 6 Mw to 7 Mw and maximum epicentre distance 15 Km. This research was performed by conducting deterministic hazard analysis, response spectral matching and site response analysis to obtain a pair of modified acceleration time histories. Site response analysis was performed by conducting 30 meters soil deposit model by taking the assumption that the position of bedrock elevation is 30 meters below the surface layer. Modified acceleration time histories were developed from a pair time histories (North-South/NS and East-West/EW direction) collected from worldwide historical earthquakes. Modified time histories were developed due to limited time histories data caused by Semarang fault earthquake source.

Development of Target Power Spectral Density Functions Compatible With Design Response Spectra

2015 ◽  
Author(s):  
Jinsuo R. Nie ◽  
Jim Xu ◽  
Joseph I. Braverman
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Seismic Analysis ◽  
General Procedure ◽  
Response Spectra ◽  
Acceleration Time ◽  
Power Spectral ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Spectral Shapes

For seismic analysis of nuclear structures, synthetic acceleration time histories are often required and are generated to envelop design response spectra following the U.S. Nuclear Regulatory Commission, Standard Review Plan (SRP) Section 3.7.1. It has been recognized that without an additional check of the power spectral density (PSD) functions, spectral matching alone may not ensure that synthetic acceleration time histories have adequate power over the frequency range of interest. The SRP Section 3.7.1 Appendix A provides a target PSD function for the Regulatory Guide 1.60 horizontal spectral shape. For other spectral shapes, additional guidance on developing the target PSD functions compatible with the design spectra is desired. This paper presents a general procedure for the development of target PSD functions for any practical design response spectral shapes, which has been incorporated into the recent SRP 3.7.1, Revision 4.

Shock Absorbing Characteristics of Floors Used for Dance Exercise

1988 ◽  
Vol 4 (3) ◽  
pp. 282-305 ◽  
Author(s):  
Peter R. Francis ◽  
Michael Leigh ◽  
Aldis Berzins
Keyword(s):  
Standardized Test ◽  
Test Method ◽  
Complex Nature ◽  
Data Sets ◽  
Acceleration Time ◽  
Testing Procedures ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Additional Procedure

The Standardized Test Method for Shock-Absorbing Properties of Playing Surface Systems and Materials (ASTM F-355) was used to evaluate the shock absorbing characteristics of 13 floors used for dance exercise. Acceleration-time histories indicated that the floors differed markedly in their shock absorbing behavior. The complex nature of the acceleration-time histories led to the conclusion that descriptors that have previously been used to quantify shock absorbing data were inadequate for the floors examined in this investigation. An additional procedure was devised in order to examine potentially injurious stresses on a performer while executing a common dance exercise movement performed on each of the 13 floors tested. It was concluded that the two testing procedures evaluated differing aspects of the shock absorbing mechanisms involved in dance exercise. However, a tentative relationship between the two corresponding data sets provided some support for the retention of ASTM F-355 as a reproducible test for the shock absorbing characteristics of floors.

Validation of FMVSS201 Featureless Headform Finite Element Model for Rotational Acceleration

2001 ◽  
Author(s):  
Saeed D. Barbat
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Fe Model ◽  
Rotational Acceleration ◽  
Acceleration Time ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Drop Tests ◽  
Constitutive Parameters

Abstract This paper demonstrates an application of the nine linear accelerometer scheme, proposed by (Padgaonkar et al., 1975), to the development and validation of a finite element model of a deformable featureless headform for rotational accelerations. Steps and procedures involved in the development and calibration of the model are also described. A set of tri-axial accelerometers was mounted at the headform center of gravity, C.G., which is located at the origin of the local coordinate axes of the headform. Three bi-axial accelerometers were also mounted at the front, left, and top of the headform’s aluminum skull and on the local coordinate axes of the physical headform. Nine linear accelerations were measured at the headform in drop tests against a rigid plate at impact speeds of 2.68, 4.0, 5.36, and 6.71 m/s (6, 9, 12, and 15 mph). The rotational accelerations of the headform were then calculated from the nine linear acceleration measurements. In the finite element (FE) model of the featureless deformable headform, a visco-elastic material law, available in the non-linear dynamic explicit code PAM-CRASH, was used to simulate the vinyl skin response during impact. The constitutive parameters of the headform’s skin material were calibrated through comparison of the headform drop simulations at various impact speeds with the corresponding tests. Headform responses, such as, resultant acceleration time histories at the headform C.G. and the rotational acceleration time histories obtained from the FE predictions of the headform responses during the drop tests simulations correlated very well with those obtained from experiments. Validation of the headform model for rotational accelerations provided higher level of confidence in the prediction capability of the model when used for interior head impact simulations with vehicle upper interior as specified by the Federal Motor Vehicle Safety Standard FMVSS 201.

Operations Management Strategy of Cable-supported Bridge using Seismic Accelerometer

2019 ◽  
Author(s):  
Seung Han Lee ◽  
Sung Woo Park ◽  
Kwang-Yeun Park ◽  
Do-Kyoun Kim ◽  
Byounghan Choi
Keyword(s):  
Operations Management ◽  
Disaster Response ◽  
Management Strategy ◽  
Response Spectrum ◽  
Free Field ◽  
Seismic Safety ◽  
Acceleration Time ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Gyeongju Earthquake

<p>This study presents the operations management strategy to respond to earthquake disasters using the acceleration records measured by seismic accelerometers installed on the primary structural elements of cable-supported bridges and those on the free fields around them. A two-step strategy in operations management is proposed for the urgent seismic safety assessment. In the first step, the seismic safety is evaluated with respect to the peak values in recorded acceleration time histories at the locations of the pylon foundation of bridge and the free field around it, and the corresponding management criteria for them are determined based on the existing disaster response manual for offshore bridges. In the second step, the peak values in displacement time histories, which are estimated from the recorded acceleration time histories, are utilized to assess the seismic safety at locations of the top and middle of pylon, and the center of girder of bridge, and the corresponding management criteria are determined based on the structural analyses under the response spectrum seismic loading. When an earthquake occurs, the safety of cable-supported bridge is evaluated urgently through comparisons of peak values in the recorded acceleration time histories and the estimated displacement time histories with the management criteria of accelerations and displacements determined in advance, respectively. The validity of the proposed strategy is verified though performing the safety assessments for several cable-supported bridges on service in Korea using the acceleration data recorded during recent Gyeongju earthquake in Korea.</p>

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