Belt Load Research Articles

The feasibility and effectiveness of belt pretensioning and load limiting for adults in the rear seat

The US Fatality Analysis Reporting System (FARS) and State Data System (SDS) for Florida, Pennsylvania and Maryland were utilised to estimate relative fatality rates and injury risk ratios between the front and rear-seat passengers, and a parametric study of rear-seat restraint parameters was performed to assess chest deflection and head excursion trends. The fatality and serious injury risk in frontal crashes is found to be higher for older occupants in rear seats than for those in front seats. In addition, the relative effectiveness of rear seats is lower in newer vehicle models, presumably due to the advances in front-seat restraint technology. The simulations demonstrate that injury risk in the rear seat can be reduced by incorporating front-seat restraint technology (load limiting and pretensioning), even in the absence of an air bag and knee bolster. A force-limiting belt with a pretensioner can maintain or reduce head excursion relative to a standard belt, while reducing thoracic injury risk. In fact, 42 sets of restraint parameters were identified that reduced both head excursion and chest deflection relative to the baseline belt.

Application of the multidisciplinary design optimization algorithm to the design of a belt-integrated seat while considering crashworthiness

Multidisciplinary design optimization based on independent subspaces (MDOIS), which is a multidisciplinary design optimization (MDO) algorithm, has been recently proposed. Since MDOIS is relatively simple compared with other MDO algorithms, it is easy to apply MDOIS to practical engineering problems. In this research, an MDO problem is defined for the design of a belt-integrated seat (BIS) while considering crashworthiness. The crash model consists of an airbag, a BIS, an energy-absorbing steering system, and a safety belt. It is found that the current design problem has two disciplines - structural non-linear analysis and occupant analysis. The interdisciplinary relationship between the disciplines is identified. Interdisciplinary variables between the two disciplines are stiffness of the seat back frame and the belt load. The interdisciplinary relationship is addressed in the system analysis step in MDOIS. Prior to each independent subspace design, values of interdisciplinary variables at a given design point are determined in the system analysis step. The determined values are passed to corresponding subspaces, and the subspaces treat the received values of the interdisciplinary variables as constant parameters throughout the subspace design. For the present example, the belt load is passed to the structural analysis subspace and the stiffness of the seat back frame is passed to the occupant analysis subspace. Determined design variables in each subspace are passed to the system analysis step. In this way, the design process iterates until the convergence criterion is satisfied. As a result of the design, the weight of the BIS and the head injury criterion (HIC) of an occupant are reduced while the specified constraints are satisfied. Since the system analysis cannot be formulated in an explicit form in the current example, an optimization problem is formulated to solve the system analysis. The results from MDOIS are discussed.

충돌을 고려한 안전띠 일체형 의자의 다분야 통합최적설계

Recently Multidisciplinary Design Optimization Based on Independent Subspaces (MDOIS), an MDO (multidisciplinary design optimization) algorithm, has been proposed. In this research, an MDO problem is defined for design of a belt integrated seat considering crashworthiness, and MDOIS is applied to solve the problem. The crash model consists of an airbag, a belt integrated seat (BIS), an energy absorbing steering system, and a safety belt. It is found that the current design problem has two disciplines - structural nonlin- ear analysis and occupant analysis. The interdisciplinary relationship between the disciplines is identified and is addressed in the system analysis step in MDOIS. Interdisciplinary variables are belt load and stiffness of the seat, which are determined in system analysis step. The belt load is passed to the structural analysis subspace and stiffness of the seat back frame to the occupant analysis subspace. Determined design vari- ables in each subspace are passed to the system analysis step. In this way, the design process iterates until the convergence criterion is satisfied. As a result of the design, the weight of the BIS and Head Injury Crite- rion (HIC) of an occupant are reduced with specified constraints satisfied at the same time. Since the system analysis cannot be formulated in an explicit form in the current example, an optimization problem is formu - lated to solve the system analysis. The results from MDOIS are discussed.

Benefits of a 3+2-point belt system and an inboard torso side support in frontal, far-side and rollover crashes

Occupants using a 3-point belt are still being injured in numerous crashes. In side collisions, occupants on the opposite side of the vehicle to the intrusion are mainly restrained by the lap part of the 3-point belt, with the associated high risk of sustaining a severe head injury. During a rollover crash, the 3-point belt cannot fully prevent harmful head impacts. In this study, an additional 2-point torso belt is combined with an inboard torso side support. The idea is to distribute the belt load on more anatomical structures (bones) and restrain the occupant in the inboard and upward directions. The inboard side support prevents direct loading by the 2-point belt to the cervical spine in far-side collisions. To assess whether this design measure is of benefit, frontal, far-side and rollover tests were performed.

Effects of a lifting belt on spine moments and muscle recruitments after unexpected sudden loading.

Ten men and eight women participated in a repeated-measures experiment in which sudden loads were applied unexpectedly to a container held in the hands. Three independent variables were investigated: lifting belt use, preload, and load symmetry. To determine whether a lifting belt would help protect the spine in sudden symmetric and asymmetric loading situations. Unexpected loading events have long been associated with the onset of back pain. Based on work showing that lifting belts restrict motion of the torso, the hypothesis was that a lifting belt would stiffen the spine, thereby protecting its supporting tissues. A weight, equal to 7.5% of the subjects' trunk extension force, was allowed to fall 1 m before the bottom of a box held by blindfolded subjects was pulled. Kinetic and kinematic data, obtained from two force plates and a magnetic motion measurement system, were used in a three-dimensional, dynamic, linked-segment biomechanical model to calculate spine moments. Electromyogram data were simultaneously obtained from eight trunk muscles. The belt reduced the forward bending of the spine during the symmetric loadings. In the men, the belt also reduced the forward flexion moment acting on the spine. The belt restricted lateral bending in the women and men, when the box was preloaded. The peak electromyogram amplitudes from posterior contralateral erector spinae and latissimus dorsi muscles increased during the asymmetric loadings, whereas three ipsilateral muscles were less active. The conflicting moment and electromyographic results, combined with the influence of load symmetry, preload, and gender make the benefits of the lifting belt difficult to delineate. Although the data support the hypothesis that the belt stiffens the torso's response to sudden loading, the effects are small, and considerable individual differences exist. The findings show that during unexpected sudden loading, a belt may reduce the net external moment loading. At the same time the belt appears to alter the muscle response strategy so that the belt's overall effect on an individual's safety is hard to determine.

Verification of Parameters in Simulation Model for Calculating Loads to Synchronous Drive Belts.

A simulation model has been developed to estimate belt load by replacing the layout (L/O) around the engine synchronous drive belt and cam pulley with a simple vibration model based on the spring-mass system. Verification of the belt load generation mechanism was made between calculated and measured belt load values based upon DOHC engines with different number of cylinders. Another verification was made for the belt load generation mechanism in the SOHC engine with different initial belt tension value. This report describes the specifications of our simulation model and the results of verification.

Toothed Belt-Load Distribution

A mathematical model was developed to study the effect on belt load distribution of belt material properties, pitch variations, friction force, and pulley rotation. Results are presented which show the influence on load distribution of pitch difference, tight side tension, slack side tension, belt tooth spring constant, and coefficient of friction, for the belt on stationary, driver, and driven pulleys. Data from the mathematical model compared well with experimental results available in the literature.

Formation of mathematical models for calculating the linear load of conveyor belts transporting coarse rock

1. As a result of using the theory for mathematical planning of experimental studies it has been possible to create mathematical models supporting information about the process of charging a belt trough and the space above the trough with mined material in relation to belt operating width, coarseness of the fractions loaded, and their percentage content of the overall volume. This in turn made it possible by a program in a Mir-1 computer to analyze the process of belt charging when the diameter of weighted mean lump size of crushed rock varies in the range 100 mm≤Dm≤900 mm. 2. With stable uniform transporting conditions the linear belt load for coarse rock located in the trough decreases with increasing weighted mean lump size Dm, and it increases for rock located above the belt trough. 3. The intensity of reduction in linear load in the trough with a simultaneous increase above the belt trough is found in a dependence on Dm and belt width (see Fig. 1a, b).