Side Curtain Research Articles

Driver Injury from Vehicle Side Impacts When Automatic Emergency Braking and Active Seat Belts Are Used.

As an advanced driver assistance system, automatic emergency braking (AEB) can effectively reduce accidents by using high-precision and high-coverage sensors. In particular, it has a significant advantage in reducing front-end collisions and rear-end accidents. Unfortunately, avoiding side collisions is a challenging problem for AEB. To tackle these challenges, we propose active seat belt pretensioning on driver injury in vehicles equipped with AEB in unavoidable side crashes. Firstly, records of impact cases from China's National Automobile Accident In-Depth Investigation System were used to investigate a scenario in which a vehicle is impacted by an oncoming car after the vehicle's AEB system is triggered. The scenario was created using PreScan software. Then, the simulated vehicles in the side impact were devised using a finite element model of the Toyota Yaris and a moving barrier. These were constructed in HyperMesh software along with models of the driver's side seatbelt, side airbag, and side curtain airbag. Moreover, the models were verified, and driver out-of-position instances and injuries were evaluated in simulations with different AEB intensities up to 0.7 g for three typical side impact angles. Last but not least, the optimal combination of seatbelt pretensioning and the timing thereof for minimizing driver injury at each side impact angle was identified using orthogonal tests; immediate (at 0 ms) pretensioning at 80 N was applied. Our experiments show that our active seatbelt with the above parameters reduced the weighted injury criterion by 5.94%, 22.05%, and 20.37% at impact angles of 90°, 105°, and 120°, respectively, compared to that of a conventional seatbelt. The results of the experiment can be used as a reference to appropriately set the collision parameters of active seat belts for vehicles with AEB.

Estimating the air exchange rates in naturally ventilated cattle houses using Bayesian-optimized GBDT

It is challenging to estimate the air exchange rate (AER) dynamically in naturally ventilated livestock buildings such as dairy houses due to the influence of complex and variable outdoor environmental factors, large opening ratios, and the confusion of inflow and outflow at openings. This makes it difficult to efficiently regulate the opening ratio to meet the ventilation requirements in naturally ventilated livestock buildings. In this study, the air exchange rates of naturally ventilated cattle houses (NVCHs) in different seasons and opening ratios were obtained through field measurements and computational fluid dynamics (CFD) simulations. A fast and efficient machine learning framework was proposed and examined to predict AER based on the gradient boosting decision tree (GBDT) combined with Bayesian optimization. Compared with commonly used machine learning models such as multilayer perceptrons (MLPs) and support vector machines (SVMs), the proposed GBDT model has higher prediction accuracy and can avoid falling easily into local optima. Compared with the existing mechanical model based on the Bernoulli equation, the proposed GBDT model showed a slightly higher prediction than the mechanistic model and was much easier to use in AER estimation when inputting easily collected environmental factors in practical applications. Using Bayesian optimization could dramatically reduce the computing time when determining the optimal hyperparameter for establishing the GBDT model, dramatically saving on computing resources. Based on the Bayesian optimized GBDT model, the desirable opening ratio of the side curtain can be determined for automatically regulating the AER of cattle houses in future applications. Keywords: natural ventilation, Bayesian, GBDT, air exchange rate, cattle house DOI: 10.25165/j.ijabe.20231601.7309 Citation: Ding L Y, E L, Lyu Y, Yao C X, Li Q F, Huang S W, et al. Estimating the air exchange rates in naturally ventilated cattle houses using Bayesian-optimized GBDT. Int J Agric & Biol Eng, 2023; 16(1): 73–80.

Smoke-mediated visualization of airflow of the booth as a negative pressure machine for a patient lying a stretcher, to whom the medical staff can approach from the window on the side curtain. A medical staff’s action is simulating the practice of tracheal intubation or suctioning that frequently generate aerosols from the patient

Smoke-mediated visualization of airflow of the booth as a negative pressure machine for a patient lying a stretcher, to whom the medical staff can approach from the window on the side curtain. A medical staff’s action is simulating the practice of tracheal intubation or suctioning that frequently generate aerosols from the patient

The performance of the booth as a negative pressure machine for a patient lying on a stretcher, to whom the medical staff can approach from the window on the side curtain. The particle count of a voluntary cough from an adult male lying in the booth and reached the face area of the dummy doctor standing outside the booth was

The performance of the booth as a negative pressure machine for a patient lying on a stretcher, to whom the medical staff can approach from the window on the side curtain. The particle count of a voluntary cough from an adult male lying in the booth and reached the face area of the dummy doctor standing outside the booth was

Factors influencing side air curtain deployment in rollover motor vehicle accidents

Objective: Recent changes in FMVSS have led to the utilization of side air curtains to provide occupant retention during rollover events. However, the safety advantage provided by the air curtains relies on the vehicle system’s ability to detect the rollover event and deploy the curtains. The purpose of this study is to identify crash and vehicle characteristics in motor vehicle rollovers that influence side air curtain deployment and occupant outcomes. The current study aims to improve the understanding of rollover events and inspire more robust air curtain deployment strategies.Methods: Study data were extracted from rollover cases documented in the NASS-CDS data set from 2011 to 2015. Vehicle model years of 2011 or later with side air curtains installed were examined. The presence of a rollover sensor in each vehicle was determined from vehicle content data available on the Insurance Institute for Highway Safety’s crash rating website. The resulting data set contained 14,003 weighted cases of rollover accidents in which the side air curtain did not deploy (40 raw count) and 23,178 cases of deployment (80 raw count).Results: Several crash event and vehicle characteristics were similar for the nondeployed and deployed groups, including number of quarter turns, primary location of damage, initiating event for the rollover, and vehicle model year. However, the nondeployed group included significantly more passenger vehicle body types (vs. SUV or truck) and had a significantly lower rate of rollover sensor presence. Presence of a rollover sensor increased the odds air curtain deployment by a factor of 36.5 (95% confidence interval [CI], 5.06–265). Cases in which both side air curtains deployed resulted in a higher frequency of injured occupants (Maximum Abbreviated Injury Scale [MAIS] ≥ 3). However, rollover events resulting in these injuries were also associated with higher rates of impact with another object or vehicle and damage to the roof of the vehicle, suggesting a higher energy event.Conclusions: Nondeployment of the side curtain airbags in rollovers occurred more frequently in vehicles without dedicated rollover sensors, which were most frequently passenger vehicles.

Factors affecting injury severity of single-vehicle rollover crashes in the United States

Objective: This study investigated the confounding effects of factors on injury outcomes for all occupants in fatal single-vehicle crashes that involved a rollover event.Method: A generalized ordered logit model was used to investigate the role of roadway attributes, environmental factors, driver characteristics, and vehicle features in injury severity outcomes for occupants. Five years of single-vehicle rollover crash data for the United States were studied.Results: Results showed that the likelihood of serious and fatal injuries increases in rollover crashes with partial or complete ejection of the occupant, no seat belt use, speeding, higher posted speed limits, roadside and median rollovers, undulating terrain, blacktop road surface, and rural roads. We also found that evening, weekdays, previous driver crash, careless or inattentive driving, driver–passenger engagement, aggressive driving, and vehicle type affect injury severity. The deployment of airbags was associated with fewer serious and fatal injuries. Regional differences were found for injury severity outcomes in rollover crashes.Conclusions: The study provides valuable insight for reducing injury severity in single-vehicle crashes where a rollover occurs. Several proven countermeasures may prevent rollovers or reduce injury severity. These strategies include increasing seatbelt use, posting lower speed limits and installing speed enforcement cameras in high-risk areas, flattening roadside embankments, and promoting in-vehicle stability enhancement systems such as electronic stability control and rollover-activated side curtain airbags.

Numerical investigation on effects of side curtain opening behavior on indoor climate of naturally ventilated dairy buildings

The side-curtain is popular in cattle buildings to regulate indoor climates and ventilation rates by adjusting the opening ratio. It normally had three different adjusting strategies relate to the position of rollers, i.e. central roller (S1), top roller (S2) and bottom roller (S3), which result in different opening behaviors to generate the same opening ratio but different opening positions in the side wall for a full-curtain house. Numerical simulations were conducted using computational fluid dynamics (CFD) to investigate the effects of the eight potential opening behaviors of side curtains on the indoor climates and airflow rates in winter for a typical naturally ventilated dairy house in China when the opening ratio were 8.5% and 17%. Airflow patterns, wind chilled temperature (WCT) and age of air were analyzed in the animal occupied zone (AOZ) by taking reference planes. Openings at the very bottom of side walls had more efficient ventilation due to the younger air age, more effective air disturbing, more uniformly distributed indicators in AOZ. However, it will result in a lower WCT in AOZ although a lower ventilation rate was observed in this case. Openings on the very top of side wall would generate a better thermal comfort in AOZ but with very poor air quality and nonuniformly distributed airflows in the dairy house. S1 was not recommended to the practical application due to the poor indoor climate and the higher cost of the mechanical structure. Based on the comprehensive evaluations of the analytic hierarchy process, the most satisfaction opening positions were at the bottom of the side curtains and the optimized adjusting strategy is S2. Keywords: thermal comfort, age of air, ventilation rate, computational fluid dynamics, analytic hierarchy process DOI: 10.25165/j.ijabe.20201305.5805 Citation: Li Q F, Yao C X, Ding L Y, Yu L G, Ma W H, Gao R H, et al. Numerical investigation on effects of side curtain opening behavior on indoor climate of naturally ventilated dairy buildings. Int J Agric & Biol Eng, 2020; 13(5): 63–72.

A Computational Fluid Dynamics Model of Biological Heat and Gas Generation in a Dairy Holding Area

Abstract.The design and operation of ventilation systems for animal housing is a crucial component in maintaining a suitable environment for both animals and workers by removing heat, moisture, and gas species. However, important design and operational criteria, such as profiles of velocity and extent of mixing within animal housing, can be difficult to study experimentally. Thus, a computational fluid dynamics (CFD) model of a commercial dairy holding area, including the generation of transport of heat and gas species within the domain, was developed. The animal-occupied zone (AOZ) was modeled using porous media. The model was evaluated with experimental data of velocity and gas concentration. Results indicated that the airflow uniformity and air speed could be increased within the holding area by modifying the configuration of the side curtain openings and using concrete walls to guide airflow; a 20% increase in average velocity within the AOZ was achieved. Results of the CFD model have shown it to be an effective tool for gaining insight into the complex mixing patterns within holding areas to improve the design of animal housing. Keywords: Animal-occupied zone, Computational fluid dynamics, Greenhouse gas emissions, Holding area.

Influence of curtain side airbag deployment to the occupant seated in child restraint system

Influence of curtain side airbag deployment to the occupant seated in child restraint system

First Side Curtain Airbag for Commercial Vehicles

First Side Curtain Airbag for Commercial Vehicles

Severe soft tissue injuries of the upper extremity in motor vehicle crashes involving partial ejection: the protective role of side curtain airbags

IntroductionPartial ejection (PE) of the upper extremity (UE) can occur in a motor vehicle crash (MVC) resulting in complex and severe soft tissue injuries (SSTI). This study evaluated the relationship between partial ejection and UE injuries, notably SSTIs, in MVCs focusing on crash types and characteristics, and further examined the role of side curtain airbags (SCABs) in the prevention of partial ejection and reducing SSTI of the UE. MethodsWeighted data was analyzed from the National Automotive Sampling System Crashworthiness Data System (NASS-CDS) from 1993 to 2012. Logistic regression models were used to assess the relationship of PE with SSTI of the UE and the effect of SCABs in both nearside impacts and rollover collisions. Crash Injury Research and Engineering Network (CIREN) case studies illustrated PE involving SSTI of the UE, and long term treatment. ResultsRollover and nearside impact collisions had the highest percentages of partial ejection, with over half occurring in rollover collisions. Annually over 800 SSTIs of the UE occurred in all MVCs. For nearside lateral force impacts, a multivariable analysis adjusting for belt use and delta V showed a 15 times (OR 15.35, 95% CI 4.30, 54.79) greater odds of PE for occupants without SCABs compared to those with a SCAB deployment. No occupants (0 of 51,000) sustained a SSTI of the UE when a SCAB deployed in nearside impacts, compared to 0.01% (114 of 430,000) when SCABs were unavailable or did not deploy. In rollover collisions, a multivariable analysis adjusted for number of quarter turns and belt use showed 3 times the odds (OR 3.02, 95% CI 1.22, 7.47) of PE for occupants without SCABs compared to those with a SCAB deployment. Just 0.17% (32 of 19,000) of the occupants sustained a SSTI of the UE in rollovers with a SCAB deployment, compared to 0.53% (2294 of 431,000) of the occupants when SCABs were unavailable or did not deploy. CIREN case studies illustrated the injury causation of SSTI of the UE due to partial ejection, and the long term treatment and medical costs associated with a SSTI to the UE. ConclusionsThe majority of severe soft tissue injuries (SSTI) of the upper extremity (UE) involved partial ejection out the nearside window of outboard seated occupants in nearside impacts and rollover collisions. Real world case studies showed that SSTIs of the upper extremity require extensive treatment, extended hospitalization and are costly. Occupants without a side curtain airbag (SCAB) deployment had an increase in the odds of partial ejection. SCAB deployments provided protection against partial ejection and prevented SSTIs of the UE, with none occurring in nearside impacts, and a small percentage and reduction occurring in rollover collisions compared to those where SCABs were unavailable or did not deploy.

Difference in dummy responses in matched side impact tests of vehicles with and without side airbags

Objective: Insurance Institute for Highway Safety (IIHS) high-hooded side impacts were analyzed for matched vehicle tests with and without side airbags. The comparison provides a measure of the effectiveness of side airbags in reducing biomechanical responses for near-side occupants struck by trucks, SUVs, and vans at 50 km/h.Method: The IIHS moving deformable barrier (MDB) uses a high-hooded barrier face. It weighs 1,500 kg and impacts the driver side perpendicular to the vehicle at 50 km/h. SID IIs dummies are placed in the driver and left second-row seats. They represent fifth percentile female occupants.IIHS tests were reviewed for matches with one test with a side airbag and another without it in 2003–2007 model year (MY) vehicles. Four side airbag systems were evaluated: (1) curtain and torso side airbags, (2) head and torso side airbag, (3) curtain side airbag, and (4) torso side airbag.There were 24 matched IIHS vehicle tests: 13 with and without a curtain and torso side airbags, 4 with and without a head and torso side airbag, 5 with and without a side curtain airbag, and 2 with and without a torso airbag. The head, chest, and pelvis responses were compared for each match and the average difference was determined across all matches for a type of side airbag.Results: The average reduction in head injury criterion (HIC) was 68 ± 16% (P < .001) with curtain and torso side airbags compared to the HIC without side airbags. The average HIC was 296 with curtain and torso side airbags and 1,199 without them. The viscous response (VC) was reduced 54 ± 19% (P < .005) with curtain and torso side airbags. The combined acetabulum and ilium force (7 ± 15%) and pelvic acceleration (−2 ± 17%) were essentially similar in the matched tests.The head and torso side airbag reduced HIC by 42 ± 30% (P < .1) and VC by 32 ± 26% compared to vehicles without a side airbag. The average HIC was 397 with the side head and torso airbag compared to 729 without it. The curtain airbag and torso airbag only showed lower head responses but essentially no difference in the chest and pelvis responses.Conclusion: The curtain and torso side airbags effectively reduced biomechanical responses for the head and chest in 50 km/h side impacts with a high-hooded deformable barrier. The reductions in the IIHS tests are directionally the same as estimated fatality reductions in field crashes reported by NHTSA for side airbags.

Validation of Event Data Recorders in Side-Impact Crash Tests

This study evaluated the accuracy of 75 Event Data Recorders (EDRs) extracted from model year 2010-2012 Chrysler, Ford, General Motors, Honda, Mazda, and Toyota vehicles subjected to side-impact moving deformable barrier crash tests. The test report and vehicle-mounted accelerometers provided reference values to assess the EDR reported change in lateral velocity (delta-v), seatbelt buckle status, and airbag deployment status. Our results show that EDRs underreported the reference lateral delta-v in the vast majority of cases, mimicking the errors and conclusions found in some longitudinal EDR accuracy studies. For maximum lateral delta-v, the average arithmetic error was −3.59 kph (−13.8%) and the average absolute error was 4.05 kph (15.9%). All EDR reports that recorded a seatbelt buckle status data element correctly recorded the buckle status at both the driver and right front passenger locations. For equipped vehicles that reported side torso, side curtain, and frontal airbag deployment information, all vehicles recorded the correct status. Although only model year 2013 and later EDRs must meet Code of Federal Regulations Title 49 Part 563, seatbelt buckle status and frontal airbag deployment time are required data elements. Language: en

Wykorzystanie indeksu termiczno� wilgotnosciowego (THI) do oceny warunk�w termiczno-wilgotnosciowych w oborach wolnostanowiskowych

The objective of this study was to evaluate temperature/humidity conditions in freestall barns with different types of gravity ventilation and to determine the risk of heat stress in cows based on the temperature-humidity index. The study was carried out during summer months (June/July) in two free-stall barns located in north-eastern Poland. The buildings for the study were selected based on the natural ventilation and animal housing systems used. One building was equipped with supply ducts mounted over windows and a roof ridge gap, and the other had flat roof exhaust ducts and side curtain. It was found from this study that the barn having flat roof exhaust ducts and air supply from side curtain was characterized by more favourable temperature/humidity conditions and presented a lower risk of heat stress to cows compared to the barn with roof ridge and air inlets. It was also found that cows in the barn with side curtain had comfortable conditions and those in the roof ridge barn were exposed to mild and moderate stress.

Repeatability of a Small Overlap and an Oblique Moving Deformable Barrier Test Procedure

NHTSA has developed two different moving deformable barrier-to-vehicle test procedures to assess the vehicle and occupant response in narrow overlap motor vehicle crashes. An assessment of test repeatability is one of the requirements necessary to accept the test procedure as viable. Previous methodologies, coefficient of variation (CV) and similarity analysis were developed to assess the repeatability of vehicle and occupant response in motor vehicle crash tests for full frontal and 40% overlap tests procedures. These will be used for this assessment. Three repeat tests were performed in each test procedure, with all other factors held constant: vehicles of the same make, model, and model year; moving deformable barriers of the same mass, velocity, and barrier face properties; and the same occupant - a THOR 50th percentile adult male in the driver's seat. In general, for this one vehicle make and model the repeatability of both vehicle and occupant response metrics were good for both test modes. In isolated cases, differences in occupant response resulted from the timing of side curtain air bag deployment. Language: en

Finite element analysis of occupant head injuries: Parametric effects of the side curtain airbag deployment interaction with a dummy head in a side impact crash

In this study, we investigated and assessed the dependence of dummy head injury mitigation on the side curtain airbag and occupant distance under a side impact of a Dodge Neon. Full-scale finite element vehicle simulations of a Dodge Neon with a side curtain airbag were performed to simulate the side impact. Owing to the wide range of parameters, an optimal matrix of finite element calculations was generated using the design method of experiments (DOE); the DOE method was performed to independently screen the finite element results and yield the desired parametric influences as outputs. Also, analysis of variance (ANOVA) techniques were used to analyze the finite element results data. The results clearly show that the influence of moving deformable barrier (MDB) strike velocity was the strongest influence parameter on both cases for the head injury criteria (HIC36) and the peak head acceleration, followed by the initial airbag inlet temperature. Interestingly, the initial airbag inlet temperature was only a ~30% smaller influence than the MDB velocity; also, the trigger time was a ~54% smaller influence than the MDB velocity when considering the peak head accelerations. Considering the wide range in MDB velocities used in this study, results of the study present an opportunity for design optimization using the different parameters to help mitigate occupant injury. As such, the initial airbag inlet temperature, the trigger time, and the airbag pressure should be incorporated into vehicular design process when optimizing for the head injury criteria.

Investigating occupant safety through simulating the interaction between side curtain airbag deployment and an out-of-position occupant

The objective of this research is to elucidate the effect of side curtain airbag deployment on occupant injuries and safety when the occupant is either in-position or out-of-position (OOP). We used side impact vehicle collision simulations with a 1996 Dodge Neon model, which was further modified to include a side curtain airbag, a seatbelt, and a 50th percentile Hybrid III dummy. The airbag used in the study was inflated using both the uniform pressure (UP) and smooth particle hydrodynamics (SPH) methods. In-position and OOP simulations were performed to assess and establish guidelines for airbag aggressivity thresholds and occupant position versus risk of injury. Three different OOP scenarios (OOP1, OOP2, OOP3) were initially setup following the work of Lund (2003), then modified such that the dummy's head was closer to the airbag, increasing the chance of injury caused by the airbag. The resultant head acceleration as a function of time for in-position and OOP simulations shows that both UP and SPH methods produce similar peak accelerations in cases where the airbag is fully inflated prior to impact. In all cases, the head peak accelerations and the head injury criteria for simulations with an airbag were significantly lower when compared with the no airbag case, which would typically indicate that the use of an airbag results in improved occupant protection during side impact. However, in the case of OOP2 and OOP3, the neck flexion forces actually increase significantly when compared with the no airbag case. This finding indicates that the HIC and neck flexion forces criterion are in conflict and that there may be a tradeoff in terms of occupant injury/safety with a side curtain airbag that is strongly correlated to the occupant position. Consequently, this study shows that safety devices result in a significant effect on occupant injury/safety when the occupant is in OOP conditions. Moreover, in some cases, simulation results show that the side curtain airbag may not make the occupant safer. This study requires further investigation of the vehicle-specific airbag and its interaction with an occupant in various OOP conditions.

Use of geostatistics on broiler production for evaluation of different minimum ventilation systems during brooding phase

The objective of this research was to evaluate different minimum ventilation systems, in relation to air quality and thermal comfort using geostatistics in brooding phase. The minimum ventilation systems were: Blue House I: exhaust fans + curtain management (end of the building); Blue House II: exhaust fans + side curtain management; and Dark House: exhaust fans + flag. The climate variables evaluated were: dry bulb temperature, relative humidity, air velocity, carbon dioxide and ammonia concentration, during winter time, at 9 a.m., in 80 equidistant points in brooding area. Data were evaluated by geostatistic technique. The results indicate that Wider broiler houses (above 15.0 m width) present the greatest ammonia and humidity concentration. Blue House II present the best results in relation to air quality. However, none of the studied broiler houses present an ideal thermal comfort.

The Effectiveness of Curtain Side Air Bags in Side Impact Crashes

The Effectiveness of Curtain Side Air Bags in Side Impact Crashes

Optimization of Vehicle Side Curtain Airbag Module Based on Computer Aided Engineering

Compared with other kinds of airbags,curtain airbag(CAB) has more complex structures and larger coverage area. The product development process depends on many module tests,sled tests and full size vehicle tests. Computer aided engineering(CAE) technology can replace tests to a great extent,also save test costs and product development time. This paper introduces the way of setting up simulation models and application of static deployment tests and free motion headform(FMH) tests to verify simulation models. In the CAB simulation,uniform pressure airbag models and computational fluid dynamics(CFD) models are all used. The uniform pressure airbag models are not able to simulate the pressure difference among different parts inside the cushion during inflating process. CFD-based CAB models are used to help the curtain airbag optimization design. Based on effective CAE simulation,the optimization analyses related to diffuser tube parameters,inflator mass flow rate and cushion folding patterns are discussed and performed in different cases. The optimization result shows that the proposed techniques are helpful to the parametric optimization design of side curtain airbag module in curtain airbag development process.