Virtual Testing Applied to Door Latch Performance Evaluation

Author(s):  
Keith Friedman ◽  
Khanh Bui ◽  
John Hutchinson ◽  
Matthew Stephens

Vehicle door latch minimum force capability testing presently utilizes uniaxial quasi-static loading conditions created toward the middle of the last century. Current technology enables more sophisticated virtual testing of a broad range of systems. Door latch failures have been observed in vehicles under a variety of conditions. Typically these conditions involve multiple axis loading conditions. The loading conditions presented during rollovers on passenger vehicle side door latches are not currently evaluated. Background on these conditions is reviewed. Rollover crash test results, rollover crashes and physical FMVSS 206 latch testing are reviewed. In this paper, the creation and validation of a passenger vehicle door latch model is described. The multi-axis loading conditions observed in virtual rollover testing at the latch location are characterized. These loads are then applied to the virtual testing of a latch in both the secondary and primary latch positions. The results are then compared with crash test and real world rollover results for the same latch. The results indicate that while a door latch in the secondary latch position may meet minimum existing uniaxial horizontal plane loading requirements, the incorporation of multi-axis loading conditions may result in failure of the latch to accomplish its intended purpose at loads substantially below the FMVSS 206 uniaxial failure loads. The findings suggest the need for reexamining the relevance of existing door latch testing practices in light of the prevalence of rollover impacts and other impact conditions in today’s vehicle fleet environment.

Author(s):  
Keith Friedman ◽  
Khanh Bui ◽  
John Hutchinson

Vehicle door latch performance testing presently utilizes uniaxial quasi-static loading conditions. Current technology enables sophisticated virtual testing of a broad range of systems. Door latch failures have been observed in vehicles under a variety of conditions. Typically, these conditions involve multi-axis loading conditions. The loading conditions presented during rollovers on passenger vehicle side door latches have not been published. Rollover crash test results, rollover crashes, and physical Federal Motor Vehicle Safety Standard (FMVSS) 206 latch testing results are reviewed. The creation and validation of a passenger vehicle door latch model is described. The multi-axis loading conditions observed in virtual rollover testing at the latch location are characterized and applied to the virtual testing of a latch in the secondary latch position. The results are then compared with crash test and real world rollover results for the same latch. The results indicate that a door latch that meets the secondary latch position requirements may fail at loads substantially below the FMVSS 206 uniaxial failure loads. In the side impact mode, risks associated with door handle designs and the potential for inertial release can be considered prior to manufacturing with virtual testing. An example case showing the effects of material and spring selection illustrates the potential issues that can be detected in advance of manufacturing. The findings suggest the need for re-examining the relevance of existing door latch testing practices in light of the prevalence of rollover impacts and other impact conditions in today's vehicle fleet environment.


2011 ◽  
Author(s):  
Don C. Stevens ◽  
Stephen Arndt ◽  
Leda Wayne ◽  
Mark Arndt ◽  
Robert Anderson ◽  
...  

Author(s):  
Jean Alain Le Duff ◽  
Andre´ Lefranc¸ois ◽  
Jean Philippe Vernot

In February/March 2007, The NRC issued Regulatory Guide “RG1.207” and Argonne National Laboratory issued NUREG/CR-6909 that is now applicable in the US for evaluations of PWR environmental effects in fatigue analyses of new reactor components. In order to assess the conservativeness of the application of this NUREG report, Low Cycle Fatigue (LCF) tests were performed by AREVA NP on austenitic stainless steel specimens in a PWR environment. The selected material exhibits in air environment a fatigue behavior consistent with the ANL reference “air” mean curve, as published in NUREG/CR-6909. LCF tests in a PWR environment were performed at various strain amplitude levels (± 0.6% or ± 0.3%) for two loading conditions corresponding to a simple or to a complex strain rate history. The simple loading condition is a fully reverse triangle signal (for comparison purposes with tests performed by other laboratories with the same loading conditions) and the complex signal simulates the strain variation for an actual typical PWR thermal transient. In addition, two various surface finish conditions were tested: polished and ground. This paper presents the comparisons of penalty factors, as observed experimentally, with penalty factors evaluated using ANL formulations (considering the strain integral method for complex loading), and on the other, the comparison of the actual fatigue life of the specimen with the fatigue life predicted through the NUREG report application. For the two strain amplitudes of ± 0.6% and ± 0.3%, LCF tests results obtained on austenitic stainless steel specimens in PWR environment with triangle waveforms at constant low strain rates give “Fen” penalty factors close to those estimated using the ANL formulation (NUREG/6909). However, for the lower strain amplitude level and a triangle loading signal, the ANL formulation is pessimistic compared to the AREVA NP test results obtained for polished specimens. Finally, it was observed that constant amplitude LCF test results obtained on ground specimens under complex loading simulating an actual sequence of a cold and hot thermal shock exhibits lower combined environmental and surface finish effects when compared to the penalty factors estimated on the basis of the ANL formulations. It appears that the application of the NUREG/CR-6909 in conjunction with the Fen model proposed by ANL for austenitic stainless steel provides excessive margins, whereas the current ASME approach seems sufficient to cover significant environmental effects for representative loadings and surface finish conditions of reactor components.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sujata Gupta ◽  
Anupam Mital

Abstract This study presents the behaviour of model footing resting over unreinforced and reinforced sand bed under different loading conditions carried out experimentally. The parameters investigated in this study includes the number of reinforced layers (N = 0, 1, 2, 3, 4), embedment ratio (Df /B = 0, 0.5, 1.0), eccentric and inclined ratio (e/L, e/B = 0, 0.05, 0.10, 0.15) and (a = 0°, 7°, 14°). The test sand was reinforced with bi-axial geogrid (Bx20/20). The test results show that the ultimate bearing capacities decrease with axial eccentricity and inclination of applied loads. The test results also show that the depth of model footing increase zero to B (B = width of model footing), an increase of ultimate bearing capacity (UBC) approximated at 93%. Similarly, the multi-layered geogrid reinforced sand (N = 0 to 4) increases the UBC by about 75%. The bearing capacity ratio (BCR) of the model footing increases with an increasing load eccentricity to the core boundary of footing; if the load eccentricities increase continuity, the BCR decreases. The tilt of the model footing is increased by increasing the eccentricity and decreases with increasing the number of reinforcing layers.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Xin He ◽  
Shiqi Ou ◽  
Yu Gan ◽  
Zifeng Lu ◽  
Steven Victor Przesmitzki ◽  
...  

Abstract For over ten years, China has been the largest vehicle market in the world. In order to address energy security and air quality concerns, China issued the Dual Credit policy to improve vehicle efficiency and accelerate New Energy Vehicle adoption. In this paper, a market-penetration model is combined with a vehicle fleet model to assess implications on greenhouse gas (GHG) emissions and energy demand. Here we use this integrated modeling framework to study several scenarios, including hypothetical policy tweaks, oil price, battery cost and charging infrastructure for the Chinese passenger vehicle fleet. The model shows that the total GHGs of the Chinese passenger vehicle fleet are expected to peak in 2032 under the Dual Credit policy. A significant reduction in GHG emissions is possible if more efficient internal combustion engines continue to be part of the technology mix in the short term with more New Energy Vehicle penetration in the long term.


2003 ◽  
Vol 1851 (1) ◽  
pp. 95-104 ◽  
Author(s):  
Dean C. Alberson ◽  
Roger P. Bligh ◽  
C. E. Buth ◽  
D. Lance Bullard

Cable or wire rope barrier was being used in the 1940s and maybe earlier for vehicle containment. Through the years the designs have changed, but engineers continue to see cable barrier as an inexpensive barrier for use in some roadside applications. Recently, cable or wire rope has gained popularity as a median barrier for the prevention of cross-median accidents. Cross-median accidents are typically violent collisions with a high probability of multiple serious injuries and deaths. Thus, the design trend is gravitating toward providing positive vehicle containment in wider medians for which barriers have not historically been warranted. Wire rope often provides a cost-effective solution for this design scenario. Field experience with cable or wire rope barriers has identified areas for design improvement. It is desirable that cables remain taut to improve interaction with the vehicle, reduce dynamic deflections, and minimize maintenance. Additionally, reduced design deflections result in more potential application sites. Recent research demonstrates that such improvements are practical and cost-effective. Besides the initial tension in the wire ropes, other factors that can have a significant influence on dynamic deflections include post spacing and horizontal curvature. Computer simulations with cable barriers with various post spacings and horizontal curvatures were used to develop guidelines for expected design deflections. Finally, full-scale crash tests were completed with a new, cost-effective cable terminal system, and a brief review of the design and crash test results is included.


Author(s):  
Donald S. Burke ◽  
Martha W. Bidez ◽  
Kathryn Mergl

According to the National Highway Traffic Safety Administration (NHTSA) rollovers have a higher fatality rate than all other kinds of crash modes. Of the 6,159,287 police reported crashes in 2005 in the United States, only 4.1% involved a rollover. Yet, rollovers accounted for 34.4% (10,816) of all passenger vehicle fatalities and another 149,406 individuals sustained serious injuries in rollover crashes in 2005 [5].


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