24 research outputs found
Methodology For Performing Whole Body Pmhs Underbody Blast Impact Testing, And The Corresponding Response Of The Hybrid Iii Dummy And The Finite Element Dummy Model Under Similar Loading Condition
In recent wars, the use of improvised explosive devices and landmines has dramatically increased as a tactical measure to counter armored vehicles. These weapons not only deform and damage the vehicle structure but also produce serious vertical deceleration injuries to mounted occupants. The reported injury patterns largely differ from those in an automotive crash and are often more severe than those in other vertical loading scenarios such as pilot seat ejection, helicopter crash, parachute landing and fall from height. High kinetic energy predominately along the principal vertical (Z-axis) over a short duration makes the underbody blast (UBB) loading conditions unique compared to other vertical and blunt impacts. With the lack of biomechanical response corridors (BRCs), the non-biofidelic nature of the automotive dummies to Z-axis loading and the lack of a finite element dummy model designed for vertical loading make it difficult to evaluate occupant response and develop mitigation strategies for UBB impact conditions.
An introduction to the development of the BRCs this study provides a detailed methodology to perform whole body cadaver testing under a laboratory setup. Two whole body PMHS UBB impact tests were conducted using a sled system. An overview of pre-impact parameters such as bone mineral density, instrumentation technique, and vertical impulse generation is presented. Post-test CT scans, response data, and possible injury mechanisms were investigated.
In addition, to PMHS testing, the responses of the Hybrid III dummy to short-duration large magnitude vertical acceleration in a laboratory setup were analyzed. Two unique test conditions were investigated using a horizontal sled system to simulate the UBB loading conditions. The biomechanical response in terms of the pelvis acceleration, chest acceleration, lumbar spine force, head accelerations and neck forces were measured during the tests.
Subsequently, a series of finite element analyses (FEA) were performed to simulate the physical tests. The material parameters of various components as well as the mesh size were updated based on the high strain rate loading conditions obtained from Zhu et.al (2015) study. The correlation between the Hybrid III test and numerical model was evaluated using the CORA version 3.6.1. The Cora score for WSU FE model was determined to be 0.878 and 0.790 for loading conditions 1 and 2, respectively, in which 1.0 indicated a perfect correlation between the experiment and simulation response. The original LSTC model simulated under the current loading condition became numerically unstable after 12 ms. With repetitive vertical impacts, the Hybrid III dummy pelvis showed a significant increase in the peak acceleration accompanied by rupture of the pelvis foam and flesh. The revised WSU Hybrid III model indicated high stress concentrations at the same location where the pelvis foam and flesh in the actual ATD showed rupture. The stress contour under the ischial tuberosities in the finite element model provides a possible explanation for the material failure in the actual Hybrid III tests
Mathematical modeling and reliability analysis of a 3D Li-ion battery
The three-dimensional (3D) Li-ion battery presents an effective solution to issues affecting its two-dimensional counterparts, as it is able to attain high energy capacities for the same areal footprint without sacrificing power density. A 3D battery has key structural features extending in and fully utilizing 3D space, allowing it to achieve greater reliability and longevity. This study applies an electrochemical-thermal coupled model to a checkerboard array of alternating positive and negative electrodes in a 3D architecture with either square or circular electrodes. The mathematical model comprises the transient conservation of charge, species, and energy together with electroneutrality, constitutive relations and relevant initial and boundary conditions. A reliability analysis carried out to simulate malfunctioning of either a positive or negative electrode reveals that although there are deviations in electrochemical and thermal behavior for electrodes adjacent to the malfunctioning electrode as compared to that in a fully-functioning array, there is little effect on electrodes further away, demonstrating the redundancy that a 3D electrode array provides. The results demonstrate that implementation of 3D batteries allow it to reliably and safely deliver power even if a component malfunctions, a strong advantage over conventional 2D batteries
Synthesis, characterization and biological studies on Co(II), Ni(II), Cu(II) and Zn(II) complexes derived from 4-(2-amino ethyl) benzene-1,2-diol and 1,4 benzoquinone
26-36A novel Schiff base ligand (L) has been synthesized using 4-(2-amino ethyl) benzene-1,2-diol (Dopamine) and 1,4 benzoquinone. Co(II), Ni(II), Cu(II) and Zn(II) complexes with this hexadentate ligand have been synthesized with metal:ligand (1:1) stoichiometry. The Schiff base ligand and its metal complexes have been characterized by elemental analysis, molar conductance, magnetic susceptibility, infrared and electronic spectra, ESR, NMR, Mass spectra, powder X-ray diffraction and SEM studies. Molar conductance showed that all complexes are non-electrolytic in nature. The Co(II), Ni(II), Zn(II) complexes are found to be octahedral and distorted octahedral structure for Cu(II) complex. Powder X-ray diffraction reveals that Schiff base ligand and its metal complexes are nano-crystalline in nature but Co(II) complex is amorphous. Different morphologies of synthesized compounds are identified by SEM images. Schiff base ligand and its metal complexes were screened against gram-positive bacteria, gram-negative bacteria and one fungus strain. The data show that the ligand and its metal complexes have significant activity. Copper(II) complex shows better activity than other complexes. The Schiff base ligand and its copper(II) complex are evaluated for the anti-inflammatory by HRBC membrane stabilization method. The anti-cancer activity of Schiff base ligand and its copper complex was also studied against human breast cancer cell line by MTT assay method. The anti-diabetic activity of Schiff base ligand and its copper(II) complex is also studied by alpha-amylase method
Synthesis, characterization and biological studies on Co(II), Ni(II), Cu(II) and Zn(II) complexes derived from 4-(2-amino ethyl) benzene-1,2-diol and 1,4 benzoquinone
A novel Schiff base ligand (L) has been synthesized using 4-(2-amino ethyl) benzene-1,2-diol (Dopamine) and 1,4 benzoquinone. Co(II), Ni(II), Cu(II) and Zn(II) complexes with this hexadentate ligand have been synthesized with metal:ligand (1:1) stoichiometry. The Schiff base ligand and its metal complexes have been characterized by elemental analysis, molar conductance, magnetic susceptibility, infrared and electronic spectra, ESR, NMR, Mass spectra, powder X-ray diffraction and SEM studies. Molar conductance showed that all complexes are non-electrolytic in nature. The Co(II), Ni(II), Zn(II) complexes are found to be octahedral and distorted octahedral structure for Cu(II) complex. Powder X-ray diffraction reveals that Schiff base ligand and its metal complexes are nano-crystalline in nature but Co(II) complex is amorphous. Different morphologies of synthesized compounds are identified by SEM images. Schiff base ligand and its metal complexes were screened against gram-positive bacteria, gram-negative bacteria and one fungus strain. The data show that the ligand and its metal complexes have significant activity. Copper(II) complex shows better activity than other complexes. The Schiff base ligand and its copper(II) complex are evaluated for the anti-inflammatory by HRBC membrane stabilization method. The anti-cancer activity of Schiff base ligand and its copper complex was also studied against human breast cancer cell line by MTT assay method. The anti-diabetic activity of Schiff base ligand and its copper(II) complex is also studied by alpha-amylase method
Synthesis, characterization, biological activities of Schiff base metal(II) complexes derived from 4-hydroxy-3,5-dimethoxybenzaldehyde and 3-aminoquinoline
1427-1436A new Schiff base ligand (E)-2,6-dimethoxy-4-((quinolin-3-ylimino)methyl)phenol (HL) and its Cu(II), Co(II), Ni(II)
and Zn(II) metal complexes have been synthesized and characterized by various spectroscopic (UV-visible, IR, NMR and
mass), SEM and magnetic susceptibility measurement. The ligand (HL) have been synthesized by condensation of
4-hydroxy-3,5-dimethoxybenzaldehyde and 3-aminoquinoline. Based on electronic spectral data and magnetic susceptibility
measurement the tetrahedral geometry is proposed for all the complexes. The ligand and metal complexes are screened for
their antimicrobial activities against bacteria (Staphylococcus aureus, Escherichia coli) and antifungal activity against the
fungi (Candida albicans). Further, the ligand and its Cu(II) complex are also screened for anticancer activity on human
breast (MCF7) cancer cell lines by the MTT assay method. Interestingly, Cu(II) complex shows better anticancer activity
than the free Schiff base ligand. The in vitro anti-inflammatory and anti-diabetic activities of the ligand and Cu(II) complex
are studied. The Cu(II) complex show higher inhibition activity than that of the free ligand
Multi-temperature state-dependent equivalent circuit discharge model for lithium-sulfur batteries
Lithium-sulfur (Li-S) batteries are described extensively in the literature, but existing computational models aimed at scientific understanding are too complex for use in applications such as battery management. Computationally simple models are vital for exploitation. This paper proposes a non-linear state-of-charge dependent Li-S equivalent circuit network (ECN) model for a Li-S cell under discharge. Li-S batteries are fundamentally different to Li-ion batteries, and require chemistry-specific models. A new Li-S model is obtained using a ‘behavioural’ interpretation of the ECN model; as Li-S exhibits a ‘steep’ open-circuit voltage (OCV) profile at high states-of-charge, identification methods are designed to take into account OCV changes during current pulses. The prediction-error minimization technique is used. The model is parameterized from laboratory experiments using a mixed-size current pulse profile at four temperatures from 10 °C to 50 °C, giving linearized ECN parameters for a range of states-of-charge, currents and temperatures. These are used to create a nonlinear polynomial-based battery model suitable for use in a battery management system. When the model is used to predict the behaviour of a validation data set representing an automotive NEDC driving cycle, the terminal voltage predictions are judged accurate with a root mean square error of 32 mV
A review of thermal management for Li-ion batteries: Prospects, challenges, and issues
Li-ion batteries are essential component in the current generation of electric vehicles. However, further pushing electric vehicles are concerned with battery life. Since the temperature dictates battery lifetime, it is crucial to manage the heat and keep the temperature at an acceptable range within the battery pack. The benefit of a cooling system is to prevent the premature degradation of battery life. This paper provides a critical review of the so far thermal management strategy dealing with temperature within the cells, module, and packs. This paper reviews the advantages and disadvantages of state of the art (traditional) thermal cooling system. In this paper, we have reviewed separately cell, module, and pack level cooling system. The battery thermal modeling techniques and cooling system design challenges are also reviewed. This paper also reviews the future cooling system for future vehicles with rising fast charge rate and these techniques can improve the limitations of the traditional cooling system. This paper also suggests the best suitable and economically viable technology for the upcoming EVs issues
Development Of Spine Injury Mechanisms, Response Corridors And Computational Human Model To Assess Mounted Occupant Injury During Underbody Blast Loading
Underbody blast (UBB) is the major cause of spine trauma in battlefields today. However, the mechanical and injury responses of the human body to such events are not well understood. The purpose of this dissertation was to simulate UBB loading conditions in a laboratory setup, and to investigate mechanisms of injury and dynamic response of thoracolumbar and sacral regions. In addition, a finite element human body model was developed for UBB applications. The outline of this study is as follows:
• A total of eleven whole-body instrumented cadavers were positioned supine on a seat-floor fixture attached to a decelerative horizontal sled. The sled and fixture impacted a concrete barrier mounted with pre-crushed honeycomb blocks, in order to simulate UBB loading conditions in a controlled environment. The input pulses were defined using the peak velocity and time to peak velocity for seat and floor and by the presence of body armor. Six loading conditions were tested. The responses measured included linear Z acceleration and Y angular velocity at the thoracic (T1, T5, T8, T12) and sacral (S1-S2) spine. Post-test computed tomography scans and autopsies were performed to identify the injuries.
• The spinal injuries generated from this study were characterized using the Denis, 1983 and 1988 classification systems and injury severity was assessed using the AIS scoring system. The injury timing was estimated based on the spine Z acceleration and Y rotational data. Furthermore, the estimated injury timing was verified by the joint time-frequency analysis performed the spine Z acceleration data.
• The underlying spinal injury mechanisms were characterized using sensor and film analysis as well as review of the literature.
• The dynamic response of the spine in terms of the influence of body armor and seat input pulse were evaluated. In addition, the trends among the magnitude of peak accelerations and time to peak acceleration on the spinal levels were investigated statistically. Furthermore, the relationship between the seat input pulse and the spine response was studied.
• A Fast Fourier transformation was performed on the spine acceleration data, wherein amplitude spectra of the spine accelerations were analyzed, and the response spectra trends between the severity levels and between fracture vs. non-fracture cases were studied. In addition, the effect of low pass filters on the data spikes associated with spinal fracture was explored. Lastly, spine response corridors with tests performed at Wayne State University were developed.
• The resulting spine response corridors were then used for modifying and validating the Global Human Body Model Consortium (GHBMC) finite element human body model for UBB applications. The modified model includes updated intervertebral discs in thoracic and spine regions. The stresses and strains generated in the spinal segments with and without fracture were analyzed.
In summary, the experimental-computational modeling approach presented in this dissertation has provided further understanding of the spine response and injury mechanisms in a simulated underbody blast environment as well as providing a potential FE design tool to help mitigate injuries
Mathematical Modeling of Transport Phenomena in Electrochemical Energy Storage Systems
Ph.DDOCTOR OF PHILOSOPH