Biodynamic Model Research Articles

Free vibration analysis of a discretized aircraft with an integrated biodynamic pilot model – modal approach

This work deals with the formulation of mathematical model for a discretized aircraft with combined seated biodynamic pilot model. The developed model provides scope for exploring the dynamic characteristics of the aircraft system and pilot under various runway operations and landing impacts. Modal analysis approach is used to obtain the free vibration characteristics of multi degrees-of-freedom system. The obtained results like natural frequencies, mode shapes and undamped response curves are reported.

Whole body active vibration control of passenger biodynamics in quarter car model under random road excitations using ANFIS gain tuned PID-super twisting control

In this research, human biodynamics in the quarter vehicle suspension model is used for studying the effect of road excitations on human body. The random road excitation is developed using ISO 8608:2016 standard for simulation work. For achieving the better ride comfort of human body, two different controllers are developed and implemented in main suspension of active quarter car model. The designed controllers include PID based super twisting control (PID-STC) and ANFIS gain tuned PID based super twisting control (AGTPID-STC). The designed ANFIS system is used to enhance the effectiveness of PID-STC controller. The ride comfort results of human biodynamic model are compared for passive and active control strategy cases for the acceleration and displacement responses. ISO 2631-1:1997 standard is also used for vibration response study in the most sensitive frequency range of 4–8 Hz for human body. Based on the simulation based graphical and mathematical results, it can be decided that AGTPID-STC controller can highly supress the undesirable effect of road induced excitaions on human body parts i.e. head and neck, upper torso, viscera and lower torso respectively compared to other control strategies.

Active Control of Uncertain Seat Suspension System Based on a State and Disturbance Observer

In this paper, an active seat suspension system that is robust to uncertainties and unknown road profiles is designed using a state and disturbance observer. The controller which needs the measurement of just the seat frame position is analyzed with a 4-degree-of-freedom biodynamic model of the passenger for performance and stability. The proposed scheme is validated by simulation for a variety of road profiles under various uncertainties and compared with passive suspension, linear quadratic regulator-based active seat suspension, and conventional active cabin suspension using the evaluation norms set by ISO-2631. The proposed scheme is seen to be robust to uncertainties in seat frame suspension, passenger mass, and cabin suspension.

Experimental Investigation on Human Walking Loading Parameters and Biodynamic Model

As part of a project to calibrate a biodynamic model of a walking person in view of the dynamic interaction with flexible structures, the paper aims at the determination of the dynamic load factors and corresponding phase angles of the Fourier series function representative of the load and the investigation on the consistency of the proposed biodynamic model. An experimental campaign was conducted with 53 people that walked individually along an instrumented rigid platform to measure the vertical ground force simultaneously to the acceleration of their waist. Expressions of the dynamic load factors were adjusted to the data and compared to results reported in the literature. The signals of the reaction forces and corresponding pedestrian accelerations are revealed to be in phase as expected by the mathematical formulation of the proposed biodynamic model. The first harmonic load factor expressed as a function of the step frequency displayed lower values compared to others researcher’s expressions. For this load factor, the subject height is shown to be a significant parameter especially for lower step frequency range in which taller people yield values up to 20% greater than shorter one did. The consistency of the proposed biodynamic model was demonstrated thus enabling the research continuity. Distinct employed procedures and pedestrian number and characteristics may explain the differences found between the present results and those of the literature. A new expression to the first harmonic dynamic load factor is offered in the paper in which not only the step frequency is considered but also the person’s height.

A Systematic Literature Review of Various Control Techniques for Active Seat Suspension Systems

Drivers of heavy trucks are exposed to large amounts of vibration which can lead to serious health risks. Many suspension systems/methods can be used to isolate these transmitted vibrations, such as vehicle suspension systems, cabin suspension systems and seating suspension systems. The central idea of the work is to identify the research gaps and raise our future research questions in this specific area. The novelty of this paper is proposing a model predictive controller for active vibration control of seating suspension systems. A systematic literature review of the existing work of the vibration control of seating suspension systems has been conducted. Various control techniques that are used in the seating suspension systems have been summarized and evaluated. This paper focusses on the biodynamic model of the driver and seat for the first step needed in the design of the seating suspension system. Then, it illustrates the different types of the system vibration controls and their performance evaluation methods. At the end, the paper details several active seating suspension systems including their actuation system structures and control algorithms which are used in the heavy vehicle trucks.

Joint effect of nanoplastics and humic acid on the uptake of PAHs for Daphnia magna: A model study

Nanoplastics (NPs) are emerging pollutants which can adsorb large amounts of hydrophobic organic compounds (HOCs) and be ingested by aquatic organisms. NPs interact with dissolved organic matter (DOM) and result in significant impacts on the bioaccumulation of HOCs in the actual environment. For the first time, the joint effects of two complex matrices on the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) to Daphnia magna (D. magna) were studied by modeling calculation. The complex matrices, nano-sized polystyrene (PS) and/or humic acid (HA), were under environmentally realistic concentrations. A biodynamic model was modified and the uptake fluxes from all exposure pathways were quantified using the experimental data. A flux estimation showed that the bioaccumulation amounts at equilibrium were mostly dependent on dermal uptake (≥99.3 % of the total). The PS matrix would retard the intestinal uptake process in D. magna, especially for the less hydrophobic PAHs; while the HA or the HA-PS matrix would facilitate the mass transfer of PAHs from the matrix to lipids in the gut. Moreover, the biota matrix accumulation factor (BMAF) were calculated to verify the biodynamic model. This work is helpful to clarify the bioaccumulation effects of PAHs in complex environmental systems.

Surface charge-dependent bioaccumulation dynamics of silver nanoparticles in freshwater algae

Silver nanoparticles (AgNPs) can gradually accumulate in algae to exert their toxicity; however, there is little knowledge about their bioaccumulation dynamics. For the first time, this study reports the effect of surface charge of AgNPs on their bioaccumulation dynamics in freshwater algae (Chlorella vulgaris) using biodynamic modeling. Polyethylene-coated AgNPs (PEI-AgNPs) and citrate-coated AgNPs (Cit-AgNPs) were selected as positively and negatively charged AgNPs, i.e., P-AgNPs and N-AgNPs, respectively. Their uptake and elimination dynamics were investigated at a concentration of 50% inhibition of growth rate values (EC50) and 10% inhibition of growth rate values (EC10). The one-component model can generally well simulate the algal uptake and elimination kinetics of N-AgNPs but not of P-AgNPs. At both concentrations, the uptake rate constants (ku) for P-AgNPs were ∼20 times higher than that for N-AgNPs. The parameters of biphasic elimination kinetics revealed that P-AgNPs were eliminated faster than N-AgNPs during depuration compared to in subsequent processes. Compared with N-AgNPs, extended Derjaguin–Landau–Verwey–Overbeek (DLVO) theory and dark-field imaging revealed that P-AgNPs can be rapidly absorbed on the algal cell surface membrane owing to their remarkably lower energy barrier between algal cells, resulting in a faster adsorption/uptake process and aggregation of algal cells. Our results clearly demonstrate that the AgNPs exhibited surface charge-dependent bioaccumulation dynamics in algal cells. Thus, AgNP surface charge primarily influences the AgNP accumulation dynamics in algal cells.

The normal vehicle forces effects of a two in-wheel electric vehicle towards the human brain on different road profile maneuver

Noise, harshness and vibrations are a non-trivial aspect of ride or human comfort, and car manufacturers often sought to improve the aforesaid comfort level. In previous studies, human biodynamic model and vehicle model are often modelled separately. Human model is used to study human alertness level and health while vehicle model is used to study on the car vibration to specifically understand the impact of vibration towards the model independently. In this study, a twelve degrees of freedom (12 DOF) human biodynamic model is incorporated with a two in-wheel electric car model to investigate the effect of vertical vibration towards the human brain based on different types of road profile and maneuver. MATLAB simulation environment is used to carry out the investigation, and it was established from the present study that the proposed model is able to provide significant insights on the impact experienced by the human brain to the skull based on the given vertical input of different road profile. The impact on the human brain to the skull is often associated with human alertness while driving where vibration exposure towards human driver influence the sleepiness level, human reaction times and lapses of attention which may lead to road accidents.

Importance of Surface Coating to Accumulation Dynamics and Acute Toxicity of Copper Nanomaterials and Dissolved Copper in Daphnia magna.

We evaluated the effect of copper oxide nanomaterials (CuO NMs), uncoated and with 3 different surface coatings (carboxylated, pegylated, and ammonia groups), on acute toxicity and accumulation dynamics in Daphnia magna. With the use of biodynamic modelling, biosorption and elimination rate constants were determined for D. magna following waterborne exposure to dissolved Cu and CuO NMs. The relationship between modeled parameters and acute toxicity endpoints was evaluated to investigate whether accumulation dynamics parameters could be used as a predictor of acute toxicity. The Langmuir equation was used to characterize the biosorption dynamics of Cu NMs and Cu chloride, used as dissolved Cu control. Uptake rates showed the following NM rankings: pristine-CuO > NH3 -CuO > aqueous Cu > polyethylene glycol (PEG)-CuO > COOH-CuO. To determine Cu elimination by D. magna, a one-compartment model was used. Different elimination rate constants were estimated for each chemical substance tested. Those that were easily biosorbed were also easily removed from organisms. Biosorption and depuration properties of NMs were correlated with zeta potential values and diameters of NM agglomerates in the suspensions. No link was found between biosorption and toxicity. Waterborne exposures to more difficult-to-biosorb CuO NMs were more likely to induce adverse effects than those that biosorbed easily. It is proposed that some physicochemical properties of NMs in media, including zeta potential and agglomerate diameter, can lead to higher biosorption but do not necessarily affect toxicity. The mode of interaction of the NMs with the organism seems to be complex and to depend on chemical speciation and physicochemical properties of the NMs inside an organism. Moreover, our findings highlight that coating type affects the biosorption dynamics, depuration kinetics, and dissolution rate of NMs in media. Environ Toxicol Chem 2020;39:287-299. © 2019 SETAC.

Dynamic Response of Biodynamic Model Seated on a Crashworthy Seat with Composite Absorber

This paper presents an energy absorber consists of an inward folding of composite tube. There is no composite debris overflow after the composites collapsing and the debris will fill in the inner of tube to increase the energy absorption. The absorber maintains integrate during crushing and then could be used in a crashworthy structure. Impact tests were conducted to explore the energy absorption performance. To investigate the application of the absorber to the shock-resistance of the seat in the helicopter, a five-degree-of-freedom nonlinear biodynamic model corresponding to 50th-percentile male occupant was setup. Simulations on the responses of the biodynamic with and without absorber were conducted, and the results present effect of the absorber on shock-resistance.

Response of human subjects using different biodynamic CAD models

Human subject suffers from many problems when it comes into contact with conditions of vibrations while travelling, working etc. in sitting posture. This result into a headache, body ache, increase in heart rate etc., therefore it becomes necessary to study the Whole body vibrations effect on human subject. Taking this into investigation, a current study has been conducted to discover the vibration effect on human subject using three different CAD models i.e. 54 kg ellipsoidal model, 76 kg solid model (single layer) and 76 kg 3-layer CAD model. All these CAD models have been modelled using 50th percentile for 54 kg and 95th percentile for 76 kg anthropometric data of Indian male population with reference from existing literature. The boundary conditions have been considered as per real conditions for different vibration conditions in sitting posture. Current study has been conducted to evaluate the mode shapes corresponding to natural frequency of each CAD model to observe the response of human subject in WBV. The comparisons of results obtained from all these CAD models have been done and it’s found that maximum deformation is obtained in head. It has been observed from the results that with a rise in natural frequency of any of the biodynamic CAD model, deformation also gets increase and also, 3-layer model found to be best model for studying the effect of WBV on human subject. The results of all CAD models have been compared and validated with the existing literature.

Whole-body vibration biodynamics - a critical review: II. Biodynamic modelling

Biodynamic models of seated body exposed to whole-body vibration are considered important for design of vibration control devices and anthropodynamic surrogates for efficient performance assessments of vibration isolators. In this second part, the reported biodynamic models of the seated body are briefly reviewed together with the different modelling approaches. The models are identified from target functions derived from the measured biodynamic responses, reviewed in the first part of this paper. Relationships between different target functions are discussed together with the merits and limitations of different modelling approaches. Further efforts are needed for developing representative target functions for deriving reliable models for designing engineering interventions and for predicting potential health and comfort effects.

Biodynamic Model of the Seated Human Body under the Vertical Whole Body Vibration Exposure

The seat-to-head transmissibility and apparent mass characteristics are measured for the seated human subjects exposed to vertical whole-body vibration in the 0.5-20 Hz frequency range at a vibration magnitude of 1.0 m/s2 rms. The experiments are conducted on test subjects seated in an upright posture. A biodynamic model has been developed for bio-mechanical parameters that are estimated on the basis of identified biodynamic responses. The parameters identification technique employs a genetic algorithm for the solution of the function comprising sum of squared magnitude and phase errors related with target values of seat-to-head transmissibility and apparent mass. The developed model presents the target values of magnitude associated with apparent mass and seat-to-head transmissibility. The natural frequencies of the model have been found at up to 5.0896 Hz. The model also presents the resonant frequencies calculated on the basis of both biodynamic response functions very close to that found for seated human body experimentally.

Waterborne and dietary accumulation of well-dispersible hematite nanoparticles by zebrafish at different life stages

The widespread use of nanoparticles (NPs) has drawn considerable attention because of their potential toxicity and the environmental consequences thereof. However, the effects of the exposure route and life stage of an organism on the bioaccumulation and toxicity of NPs are largely unknown. In the present study, we investigated the accumulation kinetics (uptake, assimilation, and efflux) and tissue distribution of waterborne and dietary hematite NPs (HemNPs) during three life stages (embryo, larva, and adult) of the zebrafish Danio rerio. For all zebrafish life stages, the waterborne accumulation of well-dispersed HemNPs increased linearly with exposure time but decreased after reaching a maximum. The increase in HemNPs accumulation followed the order embryo > larva > adult. Compared with the waterborne route, the dietary accumulation of HemNPs in larval and adult zebrafish fluctuated, reaching a maximum after each food refreshment and then decreasing until the next food addition. Similar to waterborne exposure, adult fish accumulated less dietary HemNPs than did larvae. Nevertheless, dietary HemNPs mostly accumulated in the intestinal tract, with smaller amounts in the truncus, head, and gills, as compared with their waterborne counterparts. Moreover, in the gonad no dietary HemNPs were detected whereas accumulation via waterborne HemNPs was significant. Despite the low assimilation efficiency of dietary HemNPs, biodynamic modeling showed that the diet was the main source of particle accumulation in zebrafish. Thus, both the life stage and the exposure route should be considered in evaluations of the environmental risks of NPs.

Effect of extracellular polymeric substances on arsenic accumulation in Chlorella pyrenoidosa

Inorganic arsenic (iAs) in its dominant dissolved phase in the environment is known to pose major threats to ecological and human health. While the biological effects in many arsenic-bearing freshwaters have been extensively studied, the behavior and bioaccumulation of dissolved iAS in the presence of extracellular polymeric substances (EPS) still remains to be a critical knowledge gap. In this study, the uptakes and kinetic characteristics of iAs were studied using Chlorella pyrenoidosa (a typical freshwater green algae) by addressing the different effects of EPS on arsenite (AsШ) and arsenate (AsV). The arsenic uptake capacity increased as the exposure concentration increased from 0 to 300 µmol L−1, and the uptake rate constants (Ku) in the Bio-dynamic model were greater for AsV than AsШ (0.63–11.57 L g−1 h−1 vs. 0.44–5.43 L g−1 h−1). The toxic effects as mitigated by EPS were observed through the morphological changes of algal cells by TEM and SEM. When compared with the EPS-free algal cells (EPS-F), EPS-covered cells (EPS-C) had a higher arsenic adsorption capacity through EPS-enhanced surface adsorption and reduced intracellular uptake. The overall decrease (35% and 23.3% for AsШ and AsV, respectively) in the maximum uptake capacity in intact algae cells favors cell’s tolerance to the toxic effects of iAs. These observed discrepancies between AsШ and AsV and between EPS-C and EPS-F were further elucidated through morphological images (TEM and SEM) and molecular/atomic spectroscopic data that combine three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Altogether, the spectroscopic evidence revealed the interactions of iAs with C–O–C, C–O–H and –NH2 functional groups in EPS’ tyrosine- and tryptophan-like proteins as the binding sites. Overall, this study for the first time provides comprehensive evidence on the iAs-EPS interactions. Such insights will benefit our understanding of the biogeochemical processes of iAs and the strategic development of bioremediation techniques involving microalgae in the natural and engineered systems.

Computational Modeling of Blunt Impact to Head and Correlation of Biomechanical Measures With Medical Images

Abstract Mild traumatic brain injury (TBI) is a common injury to service members in recent conflicts. We attempt to correlate simulation results with clinical data from advanced imaging techniques to identify TBI-related subtle alterations in brain morphology, function, and metabolism. Magnetic resonance image (MRI) data were obtained for a young adult male, after a concussive head injury caused by a road traffic accident. A similar fall of a pedestrian using an articulated human body biodynamics model was integrated with the finite element (FE) analysis using a high-resolution human head model to investigate TBI from an accident. The hyper-viscoelastic model was used to represent the strain rate dependence in brain tissues. The bone structure was simulated using an elastoplastic model to capture the focal permanent deformation. Enhanced tetrahedral elements were used in modeling nearly incompressible tissues. The localized large deformation in the head was simulated and compared with those from the MRI images. Biomechanical measures, such as stresses and strains, were correlated with postaccident medical images with respect to injury location and severity in the brain. The correspondence between model results and MRI findings shows a new way to relate computational simulation response of human head to blunt impacts with clinical data from such incidents and thus enhances our understanding of the mechanism, extent, and effects of TBI.

Parkinson’s Tremor Suppression Using Active Vibration Control Method

Parkinson’s disease is the second most common neuro-degenerative disorder. The hallmark symptom of Parkinson’s disease known as tremor, affects the patients in carrying out most of their daily life activities. In this paper, a biodynamic model of human arm is used to imitate the behavior of Parkinson’s tremor and suppression of this tremor is performed using a Proportional-Integral-Derivative (PID) controller which is optimized using Genetic Algorithm (GA) to obtain better performance. Active vibration controlling technique which incorporates sensors and actuators to detect and counteract the tremor is implemented with the help of PID controller.

Nonlinearity in the localised apparent masses of the seated human body exposed to vertical vibration

Abstract The apparent mass of the seated human body exposed to vertical whole-body vibration has shown nonlinear characteristics with the principal resonance frequency decreasing with increasing vibration magnitude. Experimental studies have been designed to investigate the cause of nonlinearity but there seems no consistent conclusion on the role of body parts in the nonlinearity of the apparent mass. Biodynamic modelling provides insight into effect of each model parameter on the dynamics of the system so that the contribution of individual body parts on the nonlinearity can be investigated. In this paper, a multi-body dynamic model of seated human body that can represent the dynamic forces over the local area of contact beneath the ischial tuberosities and thighs was developed. Model parameters were determined for 14 individuals who were exposed to vertical whole-body vibration at 0.25, 0.5, and 1.0 m/s2 r.m.s. in a previous study. With the model parameters determined for 14 individuals and 3 vibration magnitudes, statistical analysis was performed to confirm the effect of vibration magnitude on model parameters. The model developed in this study contained six rigid bodies representing upper-torso, lower-torso, pelvis, thighs, legs, and viscera of the body, interconnected by linear rotational springs and dampers. The geometry parameters of the model were initially derived from a finite-element model of spine and were later scaled to each of the 14 individuals. It was found as vibration magnitude increased, the vertical stiffness beneath the ischial tuberosities, the middle thighs, and the front thighs, the stiffness of viscera, the stiffness of the lower thoracic joint, and the vertical damping beneath the ischial tuberosities decreased significantly. For the vertical apparent mass, reducing the vertical stiffness beneath the ischial tuberosities and thighs and the stiffness of viscera reduced the resonance frequency, while reducing the other stiffness parameters did not see the similar effect. For the fore-and-aft cross-axis apparent mass, reducing the fore-and-aft stiffness beneath the ischial tuberosities and thighs reduced the resonance frequency, while reducing the other parameters of stiffness did not show the similar effect. It was concluded that the soft tissues beneath the ischial tuberosities and thighs and the viscera are the parts principally causing the nonlinearity observed in the apparent masses of the human body.

Evaluation of vibration reduction devices for helicopter ride quality improvement

This work presents the use of a modern helicopter simulation environment for the evaluation of the combined performance of several systems for helicopter ride quality assessment. The proposed framework can handle increasingly detailed aeroservoelastic helicopter models while providing great flexibility and versatility in modeling human biodynamic models for vibration evaluation as well as models of the vibration attenuation devices. A numerical model representative of a medium weight helicopter is used to demonstrate the approach. Lumped parameter models of seat-cushion and human biodynamics are dynamically coupled to the helicopter model to provide a more realistic estimate of the actual vibratory level experienced by the occupants. Two performance indicators are formulated, based on the acceleration of the seat locations and using the ISO-2631 standard: i) qualitative criteria and related vibration dose values of the individuals seated at prescribed locations of a fully occupied helicopter, and ii) an overall rating of the occupants inside the cabin, considering the most and least comfortable seating distributions as the number of occupants changes. To demonstrate the proposed method, three configurations of helicopter-specific passive vibration absorbers are considered.

Biodynamic Modelling of Hand for Glove Transmissibility Prediction using Artificial Neural Networks

Prediction of glove transmissibility to the hand plays an important role in order to improve its vibration reduction capability. This study presents a non-parametric biodynamic modelling of the hand based on artificial neural networks (ANNs) model for predicting the apparent mass in order to estimate the transmissibility of a glove to the hand. An experimental investigation was carried out to obtain the input-output vibration data using five subjects. Then, an ANNs model was used to map between the input and the output with its weight and bias parameters optimized using chaos-enhanced stochastic fractal search (CFS) algorithm. The results indicate that the developed ANNs hand model capable to predict the apparent mass of the human hand with an average accuracy of 97.67%.