Finite Element Analysis Simulation Research Articles

Copper Wire Bonding: A Review.

This paper provides a comprehensive review on copper (Cu) wire bonding. Firstly, it introduces the common types of Cu wire available in the market, including bare Cu wire, coated Cu wire, insulated Cu wire, and alloyed Cu wire. For each type, their characteristics and application areas are discussed. Additionally, we provide detailed insights into the impact of Free Air Ball (FAB) morphology on bonding reliability, including its effect on bond strength and formation mechanisms. Next, the reliability of Cu wire bonding is analyzed, with a focus on the impact of intermetallic compounds and corrosion on bonding reliability. Specifically, the formation, growth, and stability of intermetallic compounds at bonding interfaces are discussed, and their effects on bonding strength and reliability are evaluated. The detrimental mechanisms of corrosion on Cu wire bonding and corrosion inhibition methods are also analyzed. Subsequently, the applications of simulation in Cu wire bonding are presented, including finite element analysis and molecular dynamics simulations, which provide important tools for a deeper understanding of the bonding process and failure mechanisms. Finally, the current development status of Cu wire bonding is summarized, and future research directions are discussed.

Effect of Shape Tool Parameters on the Performance of Cold Circular Three-Dimensional Pilger Cross-Section Roll Forming

Compared with other forming processes, Pilger cold rolling exhibits unique process characteristics and a simple production method, making it highly advantageous in terms of high-precision, high-strength, and poor-plasticity alloys. Among them, the design parameters of the rolling mill play a significant role in the rolling results, with the key design parameters being the hole opening angle θ and the hole gap ΔK. In this study, a numerical simulation model for cold rolling an AZ31B magnesium alloy with variable cross-section three-roll Pilger cold rolling was established, and finite element simulation analysis was employed to obtain the comprehensive performance impact law of key design parameters on the cold-rolled AZ31B magnesium alloy. It can be concluded that when the hole opening angle is 10° and the hole gap is 1.2 mm, the equivalent stress and equivalent plastic strain of the billet reach a minimum, and the surface precision is excellent.

Freestanding fibers assembled by CoPSe@N-doped carbon heterostructures as an anode for fast potassium storage in hybrid capacitors

Although the fast development of potassium-ion hybrid capacitors (PIHC) recently, the issues such as the slow kinetics and poor durability of potassium ion hosts greatly restric their applications. Herein, a freestanding fiber (NHF fiber) with necklace-like configuration and CoPSe@N-doped carbon (CoPSe@NCNT) heterostructured units is introduced as the anode in PIHC. The highly porous network of NHF fiber facilitates the fast ion transports and promises the good high-rate property. Additionally, the nanoscle crystallites inside in-situ grown NCNT favor the high adaption to volume expansion/shrinkage and endow good structure stability during ion insertion/deinsertion. Density function theoretical (DFT) calculations disclose the CoPSe@NCNT heterostructure has improved intrinsic conductivity, fast potassium migration, and decreased energy barrier. Meanwhile, the finite element simulation analysis (FEA) reveals the decreased stress inside the NHF architecture during charge/discharge processes. Moreover, the electrochemical tests confirm the fast and durable properties of the CoPSe@NCNT NHF fibers for potassium storage. Furthermore, the PIHC full cell with the anode of CoPSe@NCNT NHF fiber is assembled, which obtains the superior energy/power densities and high capacity retention (89%) after 2000 cycles at 2 A g−1. When the polymer electrolyte is incooperated, the flexible PIHC device achieves the good pliability and good adaptation during wide temperature changes from −20 to 25 °C. Therefore, this work introduces a novel anode for fast potassium ion storage, and opens a new approach to assemble the power sources for flexible electronics in diverse conditions.

4D printing of biomimetic anisotropic self-sensing hydrogel actuators

Organisms in nature, from plants, insects to mammals, have anisotropic and regularly arranged tissue structures, which are key to rapid and precise response to environmental stimuli. In this study, nature-inspired anisotropic hydrogel actuators are fabricated by 4D printing thermo-responsive composites of short carbon fibers (SCFs) and poly(N-isopropylacrylamide) (PNIPAM). The SCFs could be well aligned and programmed in hydrogel matrix, resulting in diverse precisely controlled anisotropic structures. The intrinsic anisotropy causes unbalanced swelling and shrinking upon thermo-stimulation, leading to reversible biomimetic shape morphing. Finite element analysis (FEA) simulations are used to estimate the internal anisotropic stress distribution and structure evolution. Biomimetic anisotropic butterfly-like, flytrap-like and starfish-like hydrogel actuators are fabricated by 4D printing. On the other hand, the anisotropic SCFs/PNIPAM hydrogels are conductive and could be used as wearable strain sensors with high sensitivity. The conductive anisotropic hydrogels can generate sensing signals when they are motivated by temperature changes. This self-monitoring soft actuator is promising for the development of soft robots with stimulation-sensing-actuation feedback loop, which has broad application prospects in artificial intelligent devices.

Empirical modeling of stress concentration factors using finite element analysis and artificial neural networks for the fatigue design of tubular KT‐joints under combined loading

AbstractThe hotspot stress (HSS) approach for the fatigue design of tubular joints requires that peak HSS be known. Peak HSS in tubular joints is usually determined based on the stress concentration factor (SCF) estimated from empirical models developed through extensive experimental investigations and finite element analysis. While peak HSS usually occurs at a KT‐joint's crown and saddle points, its location may change if the tubular joint is subjected to a combination of axial, in‐plane bending, or out‐of‐plane bending loads. This study investigated the peak HSS and its location in a typical KT‐joint subjected to the combined loading. Specifically, empirical models to determine the SCF around the brace axis have been developed using extensive finite element analysis and artificial neural networks (ANN) simulations. Less than 3% error was noticed between peak HSS determined through developed models and FEA. Hence, the ANN‐based SCF equations and principle of superposition can be used to calculate peak HSS rapidly for fatigue design of tubular joints. This methodology is applicable for developing empirical models for SCF in other tubular joints and boundary conditions.

Simulation of the Circulating Bearing Currents for Different Stator Designs of Electric Traction Machines

Pulse–width modulated inverters are commonly used to control electrical drives, generating a common mode voltage and current with high–frequency components that excite the parasitic capacitances within electric machines, such as permanent magnet synchronous machines or induction machines. This results in different types of bearing currents that can shorten the service life of electric machines. One significant type of inverter–induced bearing currents are high–frequency circulating bearing currents. In this context, this work employs finite element analysis and time-domain simulations to determine the common mode current and circulating bearing current for various permanent magnet synchronous machine designs based on the traction machines of commercial electric vehicles with a focus on the stator. The results suggest that the ratio between the circulating bearing current and common mode current is much smaller in permanent magnet synchronous machines for traction applications than previously established in conventional induction machines, with values below 10% for all analyzed designs. A further increase in the robustness of such electric machines to the detrimental effects caused by the inverter supply could be achieved by reducing the parasitic winding–to–stator capacitance or by increasing the stator endwinding leakage inductance.

Magnetic Integration for Multiple Resonant Converters

A universal integration method for the magnetic components (MCs) of multiple resonant converters is proposed in this article. Two rules for integration of multiple independent MCs are summarized, one of which is to keep functional independent of MCs after integration, while the other is to achieve lower loss and volume through integration. Following the proposed rules and by dividing an MC into winding-part and nonwinding-part, integration is achieved by sharing the nonwinding-part of the MCs. An input-series output-parallel (ISOP) resonant converter is taken as an example to show how integration is accomplished step by step. It is shown that, both volume and loss of the magnetic cores are reduced after integration of all the high frequency transformers and inductors. Detailed theoretical analysis, finite element analysis simulations and comparisons have been presented. A 600 V–800 V input, 28 V/2000 W-output ISOP resonant converter was built. Experimental results have been provided to verify the effectiveness and feasibility of the proposed integration methods.

Multi-coil wireless power transfer (WPT) technique for boosting efficiency in large air gap systems

An energy-efficient high-powermulti-coil wireless power transfer system (WPT) has been studied in this paper. The proposed system was first analyzed and examined using theoretical modeling; this was followed by finite element analysis and circuit simulation to confirm the goal. As the air gap between the transmitter and receiver coils widens, the coupling coefficient of a WPT system will drop. A large-air-gap WPT system’s coupling coefficient can be raised by adding relay coils between the transmitting and receiving coils. On the other hand, an increased coupling coefficient improves the system’s overall power transfer efficiency. The suggested multi-coil system, which has an air gap of 15 cm and a lateral misalignment of 3 cm between the transmitting and receiving coils, has been simulated and verified using the Maxwell 3-D finite element tool and Ansys Simplorer circuit simulation software.

A Resonant-Type Thin Plate Piezoelectric Actuator Inspired by Koala's Locomotion

Imitating the behavioral traits or structures of biological organisms can provide new ideas and operating principles for designing micro actuators. Inspired by the locomotion of koalas, a lightweight self-locomotion piezoelectric actuator (SLPA) is developed. Based on the hybrid of the longitudinal and bending vibration modes, the proposed SLPA is able to obtain linear locomotion. The configuration of the SLPA is designed based on a thin metal plate with miniature size of 19.5×19.5×1.1mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . The operating principle is verified through the finite element analysis (FEA) simulation. The experimental results show that the prototype achieves maximum speed of 61.68 mm/s and slope angle of 20° when the excitation frequency and voltage are 19.75 kHz and 50 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p-p</sub> , which demonstrates the validity of the proposed SLPA climbing on slopes and the effectiveness of the proposed operating principle. Furthermore, the step displacement resolution of 2.2 μm is obtained by the proposed SLPA under the resonant working state. Finally, a simple optical focusing system is established to verify the feasibility of potential application of micro piezoelectric actuator.

Cryogenic System Preliminary Design for a 0.5m-Long, Conduction-Cooled Nb3Sn Undulator Magnet Prototype

There are several NbTi superconducting undulator (SCU) magnets currently in operation at the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The development on Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn-based superconducting undulator magnets at APS is underway due to the potential to further enhance the performance of the SCUs. Superconducting undulator magnets need to keep temperature gradients minimized in order to retain thermal and operating current margin. We have designed the thermal links for efficient heat conduction using 3D finite element analysis (FEA) simulation in COMSOL Multiphysics software, which was later used for the calculation of the temperature distribution across a 0.5 m long, conduction-cooled, Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn undulator magnet prototype that includes both conductive heat transfer and radiative heating components. We have modelled the evolution of the thermal properties of the magnet winding as well as other cold parts during cool-down from ambient temperature with the operation of a SHI RDK-415D cryocooler to examine the estimated time that is needed for the cooldown as well as the baseline temperature we could achieve. A key result was that a maximum coil <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Delta $</tex-math></inline-formula> T = 0.11 K along the designed thermal links and a temperature range of 3.42 K–3.53 K for the winding were predicted at steady state. A pair of G10 support rods for carrying the magnet as well as a pair of current leads made of metals were also designed and optimized for the testing system, targeting for an operation temperature of 4 K and a coil current of 950 A DC.

Optimization, finite element simulation, fractography and tool wear analysis during SPIF process of perforated stainless steel sheets

The paper deals with an investigation on the single point incremental forming (SPIF) of perforated SS 304 L sheet, to optimize various input parameters, perform the finite element simulation of the SPIF using optimum process setting, conduct fractographic analysis, and to do the wear analysis of the forming tool. The study was conducted with 18 experiments as per Taguchi’s orthogonal array, to evaluate the impact of input parameters on responses. Straight groove and wall angle tests were performed separately, to obtain the maximum sum of strains (Σε)max and maximum wall angle (ϕmax) respectively. The tool wear in terms of reduction in length was measured using a profile projector. The optimization was carried out using the Taguchi grey relational analysis (TGRA). ANOVA was employed to share out the variability brought on by the input parameters. The optimal set of forming parameters was identified, and the confirmation experiment served to confirm it. The effect of all input parameters on the responses were studied referring to the main effect plots. The tool was hardened to bring down the wear and it was confirmed by performing the experiment. FE simulation was done using Abaqus software and the results were in better agreement with that of the experiment. SEM micrographs were taken, analyzed and the fracture mode was identified to be ductile.

Thermal Analysis of Leakage Currents of No-Insulation HTS Racetrack Coils Using a Three-Dimensional Turn-Distributed Equivalent Circuit FEA Model

In promoting novel products with superconducting magnets to transportation and science industries, the most important factor is reliability. Recently, it was reported that a no-insulation (NI) superconducting magnet could be damaged with quenches caused by a thermal runaway, significant temperature deviation, extremely high characteristic resistance, etc. To resolve this issue, numerical analysis of high-temperature superconducting (HTS) racetrack coils with NI winding technology should be conducted. The authors proposed a homogenization method to analyze operating characteristics of the NI HTS coils by simplifying the finite element analysis (FEA) model and decreasing the solution time. In order to estimate their thermal stabilities, the proposed FEA simulation is one of the efficient methods for solving the electrical and thermal factors simultaneously. In this paper, the thermal analysis of the leakage currents of NI HTS racetrack coils is presented using a three-dimensional (3D) turn-distributed equivalent circuit FEA model. The charging and discharging delay phenomena were modeled by considering the contact resistances by turns. With the equivalent circuit model of the NI HTS magnets, the 3D racetrack coils were designed by considering a single turn and stacked turns, including metal insulation layers. Their material properties according to temperature variation were applied in the transient analysis. The critical currents by turns were estimated by considering the magnetic field, its angle, and temperature with a given current simultaneously. The simulation results were compared with a fabricated NI HTS magnet and are presented in this paper.

Sustainable fabrication of 3D printing filament from recycled PET plastic

The widespread use of plastic is leading to increased plastic waste and environmental concerns globally. This research paper aims to address this issue by investigating the potential of creating a sustainable 3D printing filament using recycled polyethylene terephthalate (PET) bottles. Our experimental setup involved a 1.6 mm diameter nozzle with a heater block to ensure precise temperature control during filament extrusion, resulting in a reliable and repeatable filament diameter of 1. 65 mm.The study focuses on creating a consistent filament with a 1.65 mm diameter using recycled PET bottles. Additionally, finite element analysis (FEA) is conducted using SolidWorks software to compare the mechanical properties of the PET filament to conventional polylactic acid (PLA) material widely used in 3D printing. The FEA simulations analyze stress, strain, and displacement for both PET and PLA materials, and the results are compared to draw conclusions based on the numerical observations. The findings from this research will offer valuable insights into the potential of recycled PET bottles as an environmentally friendly alternative for 3D printing filaments. This work contributes to reducing plastic waste and promotes sustainable practices in additivemanufacturing.

Multiscale static and dynamic mechanical study of the Turritella terebra and Turritellinella tricarinata seashells.

Marine shells are designed by nature to ensure mechanical protection from predators and shelter for molluscs living inside them. A large amount of work has been done to study the multiscale mechanical properties of their complex microstructure and to draw inspiration for the design of impact-resistant biomimetic materials. Less is known regarding the dynamic behaviour related to their structure at multiple scales. Here, we present a combined experimental and numerical study of the shells of two different species of gastropod sea snail belonging to the Turritellidae family, featuring a peculiar helicoconic shape with hierarchical spiral elements. The proposed procedure involves the use of micro-computed tomography scans for the accurate determination of geometry, atomic force microscopy and nanoindentation to evaluate local mechanical properties, surface morphology and heterogeneity, as well as resonant ultrasound spectroscopy coupled with finite element analysis simulations to determine global modal behaviour. Results indicate that the specific features of the considered shells, in particular their helicoconic and hierarchical structure, can also be linked to their vibration attenuation behaviour. Moreover, the proposed investigation method can be extended to the study of other natural systems, to determine their structure-related dynamic properties, ultimately aiding the design of bioinspired metamaterials and of structures with advanced vibration control.

Investigation of residual stress formation mechanism with water jet strengthening of CoCrFeNiAlx high-entropy alloy

This study investigates the strengthening mechanism of water jet (WJ) on the high-entropy alloy CoCrFeNiAlx (x = 0, 0.6, 1). Finite element simulation analysis was conducted to examine the changes in residual stress, surface roughness, and stress triaxiality of high-entropy alloys under different jet velocities and Al contents. Subsequently, an experimental validation of surface roughness was performed using the Al1 high-entropy alloy. The results reveal that the residual compressive stress and maximum residual compressive stress on the high-entropy alloy's surface increase with the jet velocity, irrespective of the Al content. However, the depth of the maximum residual compressive stress decreases as the Al content increases. At a jet velocity of 280 mm/s, the residual compressive stress on the surface of the Al1 high-entropy alloy surpasses that of the Al0.6 high-entropy alloy. Specifically, the residual compressive stress on the surface of the Al1 high-entropy alloy is approximately 265 MPa, which is significantly higher than the value of 9 MPa for the Al0.6 high-entropy alloy. When the jet velocity reaches 300 mm/s, the surface residual compressive stress of the high-entropy alloys shows a positive correlation with the Al content. The residual compressive stress on the surface of the Al1 high-entropy alloy is about 1.89 times and 1.23 times that of the Al0 and Al0.6 high-entropy alloys, respectively. As the jet velocity continues to increase to 320 mm/s, the maximum residual compressive stress of the high-entropy alloys follows the order: Al0.6 > Al0 > Al1. The maximum residual compressive stress of the Al0.6 high-entropy alloy measures approximately 477 MPa, which is approximately 82 MPa higher than that of the Al0 high-entropy alloy. Subsequently, at a jet velocity of 340 mm/s, the Al0.6 high-entropy alloy exhibits the highest maximum residual compressive stress, reaching a value of 650 MPa.Additionally, a negative correlation between surface roughness and jet velocity is observed. Moreover, an increase in Al content within the high-entropy alloys significantly reduces surface roughness under the same jet velocity impact.

A numerical investigation on the influence of full vs perimeter arrays on the mechanical reliability of electronic assemblies under vibration

PurposeThis paper aims to compare and evaluate the influence of package designs and characteristics on the mechanical reliability of electronic assemblies when subjected to harmonic vibrations.Design/methodology/approachUsing finite element analysis (FEA), the effect of package design-related parameters, including the interconnect array configuration, i.e. full vs perimeter, and package size, on solder mechanical stresses are fully addressed.FindingsThe results of FEA simulations revealed that the number of solder rows or columns available in the array, could significantly affect solder stresses. In addition, smaller packages result in lower solder stresses and differing distributions.Originality/valueIn literature, there are no papers that discuss the effect of solder array layout on electronic packages vibration reliability. In addition, general rules for designing electronic assemblies subjected to harmonic vibration loadings are proposed in this paper.

Design and development of a low-cost 5-DOF robotic arm for lightweight material handling and sorting applications: A case study for small manufacturing industries of Pakistan

Due to the ever-increasing demand for higher production rates and the shortage of skilled labor in small industries, material handling and sorting have become extremely tedious and challenging. Industrial automation-led effective material-handling solutions like robotic arms have gained immense importance as they provide an alternative to human involvement, contribute to higher sorting accuracy, and provide enhanced safety. However, the adaptability of these robotic arms in small manufacturing industries in Pakistan is mainly hindered due to their higher costs and concerns with their structural durability. This paper presents the development of a low-cost 5-DOF robotic arm with a designed payload limit of 1 kg and automatically sorts objects fed through a conveyer belt. Catering to the compact sizing, high strength, and lower payload requirements of small industries, aluminum was selected as the material of the robotic arm due to its superior strength-to-weight ratio while being lightweight. Arm geometry was developed using SOLIDWORKS® software, which was further processed in ANSYS® software to perform the static structural analysis of the robotic arm using Finite Element Analysis (FEA). The fine meshing of the robotic arm assembly was done using triangular elements with the total number of elements and total nodes 52134 and 89104, respectively. A single point load was applied on the end effector, and the force was kept downward with an incremental loading of 1 kg starting from 100 g. These FEA simulations show that the robotic arm can hoist considerable weight while maintaining its structural integrity and directionality. The proposed robotic arm is also well-suited for manipulating objects in tight spaces due to its compact size and customizable range of motion, making it an ideal choice for applications that require precise manipulation of light loads.

Finite Element Simulation and Stress Analysis of Gas Turbine Blade Due to Centrifugal Force

Gas turbine always consider one of the most important system in the modern engineering applications, because it has continuous ability to generate electric power. In gas turbines the major portion of performance dependency lies upon turbine blade design ,the blades are considered one of the important and expensive parts in the gas turbines , where the blades of first stage from failure . Most studies indicate that 50% of failure and breakage accidents cannot be accurately determined due to the large number of variables .The blades of the gas turbine suffer from tensile stresses due to centrifugal forces resulting from the high rotational speed and because of the loading of dense gasses at a high temperature and speed ,as the centrifugal force is one of the problems that the designer of the turbine blades faces , as the designer aims to reduce stresses within the permissible limit . The current work is concerns with study and analysis of the stresses at the first stage blades in Al Mosul power station at Mosul city, AUTOCAD which is computer program has been an efficient software to draw and specify blade dimensions at the exact measurement, as well as the ANSYS 21 software program was also used as an effective tool in determining the stresses and deformation under the influence of centrifugal force. As the blade was considered root bound in all direction (X, Y and Z) and adding the special mechanical properties of (INCONEL738 alloy), After conducting a stress analysis in the program, it was found that the stress values of the posterior and anterior edge of the blade root region were high and these results were validated with the results carried out by some studies that dealing with study and analysis of the blades at the first stages in turbine stations. The static and modal analysis of the turbine blade is being considered. To analyze these aspects, the blade is represented using the 3D-Solid Brick element. The blade's geometric model is created by generating and then extruding them to form a solid model. An analytical approach is utilized to estimate the centrifugal forces. The objective of this presented work is to investigate the impact of mechanical analysis on the structure of gas turbine blades. The findings indicate lower levels of mechanical stress.

Novel four-port RF phase change switches based on GeTe thin film

An indirect-heated phase-change switch (PCS) using germanium telluride (GeTe) has been fabricated using thermal actuation driven by thin film heater on the model. Switches require a low ON-state resistance and a high OFF-state resistance with OFF/ON resistance ratio of 105. The finite element analysis simulation is applied to simulate the temperature of individual node GeTe with different microwave heating pulses. Finally, in order to reduce the phase-change time and increase the switching speed of indirectly heated switching structures, a new four-port indirectly heated phase change switching structure is proposed. In this paper, the heat dissipation of the switch is increased by etching deep grooves on the back of the switch. This structure obviously reduces the phase change time compared to conventional indirectly heated phase change switches the time between ON-state and OFF-state is reduced by more than 19% and the total process is reduced by more than 47%. The GeTe PCSs with etched grooves not only significantly increases the switching speed, but also reduces the risk of recrystallization of the phase change material.

Numerical Analysis of the Impact Resistance of Composite A-Shaped Sandwich Structures.

This paper focuses on the finite element analysis simulation of the impact properties of composite sandwich structures made of carbon fiber-reinforced polymer lamina. In the existing studies, the composite sandwich structures with A-shaped cores have superior mechanical properties under quasi-static plane compression loads compared to W-shaped, Y-shaped, and X-shaped cores. However, there is limited research on the impact resistance of this structure. This paper studied the resistance of a composite A-shaped core structure to ballistic impact. Using ABAQUS/explicit finite element analysis software, ballistic impact tests for the composite A-shaped core structure were simulated based on the Hashin and Yeh failure criteria with a progressive damage model introduced in the user-defined subroutine VUMAT. First, the composite Y-shaped core sandwich structure was verified via experiments and simulations to determine the accuracy of the method, and then the composite A-shaped sandwich structure was subjected to a series of ballistic impact simulations. With varied impact velocity, the damage to the front and rear face sheet and cores via ballistic loads was simulated to illustrate the overall dynamic response process of the sandwich structure. Subsequently, a curve was fitted using a ballistic limit velocity equation, which was used as the criterion to evaluate the impact resistance of the composite A-shaped core structure. The results showed that, under the same relative density and the same number of component layers, the ballistic limit velocity of the composite A-shaped core sandwich structure was bigger than the composite Y-shaped core sandwich structure. The composite A-shaped core structure had 12.23% higher ballistic limit velocity than the composite Y-shaped core, indicating the impact resistance capabilities of the A-shaped core structure. In addition, the impact location's effect on the impact response was investigated.