Earticle

Carton clamps and forklift attachments allow users to efficiently handle shipping units including unitized loads, large shipping cases, and crates without the need for pallets. As the use of palletless handling by clamp trucks increases, the need for simulation research on clamp truck handling also grows. This study defines an analysis model for a segment of a heavyweight corrugated package (HCP) (L ×W× D = 1,003 × 980 × 1,880 mm, weight = 1,760 N). Finite element analysis (FEA) evaluated the slippage of the HCP under various conditions, using a representative load. The FEA results indicated minimal change in slippage beyond a certain clamping pressure. The slippage was lowest when the rubber contact pad on the carton-clamp truck arm was trapezoidal. Additionally, the slippage of HCP was reduced by more than 50% when using double-wall corrugated paperboard compared to single-wall corrugated paperboard. Under the same conditions, the error between the minimum clamping pressure estimated by the improved minimum clamping pressure model and the pressure analyzed through FEA was approximately 12%. Thus, if the physical properties used in FEA are enhanced, the FEA-based simulation technique can more accurately estimate the minimum clamping pressure during carton clamp truck handling.

‘Eve 58-1’, the subject of this study is a statue made of plaster and its structural stability was evaluated by utilizing the CAE program in order to prevent the risk of damage arising from impact and vibration that are generated during the packaging and transportation process given its material characteristics. CAE is an abbreviation for Computer Applied Engineering for realization by predicting changes at the time of application of virtual physical energy. It is applied by reflecting the physical property conditions and each boundary condition of plaster, and the digital images of the internal and external structure of the work were acquired through 3D scanning and CT analysis for interpretation by executing finite element modeling. When acceleration is applied to the work in the direction of its own weight, the left-right side and the front-rear side, it was possible to confirm a maximum displacement value of 15.24 mm in the head section of the front-rear side direction that has been tilted by approximately 27° from the Y-axis and the largest stress value of 12.46 MPa was at the left ankle section. The corresponding results confirmed that the left ankle section is the most vulnerable area and the section for which precautions need to be exercised and supplemented at the time of transporting the work by means of objective values.

This study investigates the structural stability of a telescopic arm designed for a painting robot through finite element analysis (FEA). As factory automation progresses, robots are increasingly used to replace hazardous tasks like painting. However, the heavy weight of telescopic arms poses significant control challenges. This research specifically examines the structural stability of a 7.4-meter telescopic arm, designed for use in a 14m x 14m large-scale block painting environment. The telescopic arm consists of six steel links, each ranging from 700 mm to 1500 mm, and supports a 50 kg painting robot mounted at the end of Link 6. Using Dassault System’s Abaqus2022 software, simulations were performed in both stretched and rotated modes to analyze self-weight effects and structural stability. The results revealed maximum deflection of 92.3 mm in stretched mode and 127.3 mm in rotated mode, with the highest stress concentration of 416.8 MPa occurring at the Link 3 and Link 4 connection. To improve stability, additional reinforcement materials and an increase in connector thickness from 40 mm to 80 mm were applied, successfully reducing maximum stress to 94.3 MPa. These findings suggest an effective enhancement in the stability of the telescopic arm under various operational modes.

Interest in modular buildings has surged recently, leading to their construction at increasing heights. However, seismic performance evaluations for modular connections remain insufficient. Based on Jang's (2019) experimental research, this study validates an analytical model and conducts parametric analyses on the shear strength ratio between the panel zone and beam, and the width-to-thickness ratio of the bracket. When the panel zone-to-beam shear strength ratio was 1.5 or higher, plastic hinge formation shifted from the panel zone to the beam. Consequently, a shear strength ratio between 1.5 and 2.0 is recommended. Analysis of the bracket’s width-to-thickness ratio revealed local buckling in models with non-compact sections, suggesting that brackets in modular connections be designed with compact sections or greater to enhance structural performance.

V-type coupling, which is often applied to turbochargers, is a mechanical fastener where radial forces close turbine housing and bearing housing together. It prevents leakage of exhaust gases by contact pressure of the backplate caused by the load transmitted from the bolt-tightening torque. Therefore, it is important to study the mechanical behaviors of the coupling system in order to establish more accurate sealing assessment technologies. In this study, an experiment was first conducted to obtain the relationship between torque and its resulting axial force in a specially designed gage bolt. Strains were then measured when the torque was applied using the gauge bolts on the turbocharger. Thus, the magnitude of the axial force due to the bolt torque can be obtained inversely. In addition, the circumference and width strains of the turbocharger coupling were measured under the assembly load, and theses results were compared with the finite element results. As a result, they tend to be very similar, but in the ring area, analysis results show a relatively small value, and near the bolt, the analysis results are larger than the experimental strains. This is thought to be due to the reduced strains around the bolt by the hammering process.

Purpose: This study is for the prosthesis of dogs. Observe the occlusal relation between the dog’s canine and carnassial teeth. The strength and the direction of the occlusal by 3D FEM analysis. Methods: The mandibular canine and carnassial of dogs were tested. The dog’s skull was contact point confirmed by dental CAD. The skull of the dog was 3D modeled by CT. The 3D model was analyzed by ABAQUS. Opening and closing movement has been a force of 100N, 200N, 300N, 500N, 1000N, 1,500N. The peak von Mises stress distribution was confirmed. Results: As occlusal force increased, stress appeared to 1.34 ㎫, 3.32 ㎫, 5.00 ㎫, 6.19 ㎫, 5.58 ㎫, 5.47 ㎫ in left canine. and Stress was seen at 2.10 ㎫, 3.08 ㎫, 3.89 ㎫, 5.50 ㎫, 7.04 ㎫, 7.18 ㎫ in the right canine. Stress appeared at 2.41 ㎫, 3.53㎫, 5.15 ㎫, 7.28 ㎫, 31.26 ㎫, 67.22 ㎫ in the left carnassial. and Stress was seen at 1.57 ㎫, 2.96 ㎫, 3.76 ㎫, 6.01 ㎫, 20.94 ㎫, 64.38 ㎫ in the right carnassial. Conclusion: Peak von Mises stress values were found at the peak of the canine, the buccal of the central cusp of the carnassial, and the occlusal surface of the distal cusp.

Purpose: The purpose of this study was to analyze the biomechanical properties of the dental implants on the supporting bone using three-dimensional finite element method when three different abutment materials were applied to the implant system. Methods: Three different dental implant models were fabricated by applying Ti, PEEK, and CRE-PEEK (60% carbonreinforced PEEK) to abutment material. The abutment and connecting screw from the fixture was applied with a tightening torque of 20 Ncm. And then, total loads of 150 N were applied in an 30°oblique direction (to the vertical). The structural stability of dental implants on the supporting bone was analyzed using Von Mises stress and principal stress values. Results: The maximum tensile stress of the cortical bone was highest at 12.6 MPa in the PEEK abutment (Model-B). Ti abutment (Model-A) and CRE-PEEK abutment (Model-C) showed similar stress distributions (10.6 and 10.3 MPa, respectively). And the maximum compressive principal stress was similar in all models. The Von Mises stress value delivered to the bone around the implant was highest at 16.5 MPa in Model-B. On the other hand, Model-A and C showed similar stress distributions (14.0 and 13.8 MPa, respectively). In addition, the maximum equivalent stress applied to the abutment was highest at 629.8 MPa in Model-A. The stress distribution in Model-C was 573.9 MPa. Whereas, Model-B showed the lowest value at 165.6 MPa. Conclusion : The dental implant supporting bone system using PEEK material seems to have the possibility of supporting bone fracture. It was found that the CRE-PEEK abutment can reduce the elastic deformation and reduce the stress value of the interfacial bone.

척추경 나사못 시스템은 척추경 나사못, 종구조물, 횡연결 기기 등으로 구성되어 있으며, 척추경을 통해 척추 전·후방에 안정성을 부여할 수 있고 견고한 고정이 가능하기 때문에 퇴행성 디스크 수술 등에 널리 사용된다. 척추경 나사못 시스템의 물리·기계적 특성 평가에 관한 규격은 ASTM F1717-18: Standard Test Methods For Spinal Implant Constructs in a Vertebrectomy Model이 있으며, 척추체 절제술 모델에서 척추용 임플란트의 정적 및 동적 피로 시험 을 위한 지그를 비롯한 실험 환경 및 시험방법을 제시하고 있다. ASTM에서는 인공 엉덩이 관절 및 인공 무릎 관절 에 대해 유한 요소 분석을 이용하여 응력과 변형률을 평가하는데 적용할 수 있도록 하고 있으나 척추경 나사못 시스 템에 관해서는 규격이 없는 실정이다. 본 연구에서는 척추경 나사못 시스템에 ASTM F1717을 적용하여 압축, 인장 및 비틀림 하중에서 물리·기계적 데이터를 도출하고, 동일한 하중 조건을 유한 요소 분석에 적용하여 실험 데이터와 비교 하였다. 이를 통해 척추경 나사못 시스템의 물리·기계적 평가에서 있어서 유한 요소 분석의 적용 가능성을 확인 하고자 하였다. 척추경 나사못 시스템의 실험 값과 유한 요소 분석 값을 비교한 결과 ASTM F1717에 따른 정적 압 축 하중 하에서 강성도, 항복 하중은 유사한 값을 보였다. 따라서, 본 연구의 결과를 통해 유한 요소 분석은 척추경 나사못 시스템의 물리·기계적 특성을 평가하는데 있어서 제한적이지만 활용 가능할 것으로 판단된다.

The pedicle screw system consists of pedicle screws, steel rods and a transverse connecting device. It can be used for treatment of degenerative disc herniation because it can provide stability through two pedicles and can be firmly fixed. ASTM F1717-18 is the standard for evaluating the physical and mechanical properties of the pedicle screw system, and it presents the experimental environment and test method including the jig for the static and dynamic fatigue test of the spinal implant in the vertebral body resection model. ASTM allows the use of finite element analysis for artificial hip joints and artificial knee joints to evaluate stress and strain, but there is no standard for the pedicle screw system. In this study, physical and mechanical data were obtained under compression, tensile and torsional loads by applying ASTM F1717 to the pedicle screw system, and the same loading conditions were applied to the finite element analysis and compared with the experimental data. In this paper, the applicability of the finite element analysis to the physical and mechanical evaluation of the pedicle screw system was investigated. Comparisons of experimental and finite element analyzes of pedicle screw system showed similar values o f stiffness and yield load under static compressive load according to ASTM F1717. Therefore, the results of this study suggest that the finite element analysis can be used to evaluate the physical and mechanical properties of the pedicle screw system.

Liquid hydrogen, a promising energy carrier, necessitates robust storage and transportation systems due to its extremely low boiling point. Consequently, the development of reliable cryogenic adhesives and standardized testing protocols is crucial. This study focused on optimizing the design of a gripper used in single lap shear tests for evaluating cryogenic adhesives, specifically targeting the challenges posed by low-temperature conditions that induce slippage at the gripper interface. The optimal design was performed using a total of five variables, including the position and size of the gripper. By employing the genetic algorithm coupled with finite element analysis, we exhaustively searched through over 1000 models to identify the optimal gripper geometry. We successfully minimized stress concentration at the gripper region while maintaining a uniform stress distribution on the non-bonded surface. Furthermore, the study explored the impact of symmetric versus asymmetric gripper configurations on test results. The findings revealed that symmetric grippers generally yielded more consistent and reliable data. This study's results enable the accurate and stable execution of lap shear tests under the temperature conditions of liquefied hydrogen.

In this study, a finite element analysis was used to analyze the stress state and vibration characteristics generated by continuous contact between wheels and rails when driving urban railway vehicles. The rails applied to the analysis were divided into straight and curved shapes, and three-dimensional modeling was performed to analyze the changes in structural characteristics of wheels and rails when driving on straight and curved rails. As a result of the analysis, the stress characteristics were up to 6.5 MPa on a straight rail and 9.81 MPa on a curved rail, and it is believed that this increase in stress will increase noise due to an increase in friction at the interface. The vibration characteristics of the wheels and rails showed similar behavior from the 3rd mode to the 9th mode of the rail to the intrinsic vibration characteristics from the 4th mode to the 6th mode of the wheel.

This study investigates the thermo-mechanical behavior and residual stress characteristics of friction stir welding (FSW) in an aluminum inverter housing using finite element analysis (FEA). FSW experiments were first conducted under various tool rotation and traverse speed conditions, and temperature histories were measured using K-type thermocouples. The optimal process condition was identified through tensile testing, and the heat input was estimated by comparing experimental and numerical results. The estimated heat source was incorporated into a transient thermal elasto-plastic analysis to evaluate deformation and residual stresses in an inverter housing model. The results indicated that residual stress distributions varied depending on the welding start position. In particular, when welding started at P3 (near thick ribs and bosses) residual stresses were reduced by approximately 30% compared to P1, owing to the higher local stiffness and enhanced heat dissipation that mitigated temperature gradients. Conversely, welding initiated at P1, a flat region with insufficient reinforcement, resulted in higher stress concentrations. These findings confirm that the welding start position significantly influences residual stress behavior in inverter housings and provide fundamental insights for developing residual stress control strategies in FSW of large-scale components.

ROPS is a structure installed to protect drivers from tractor rollover accidents and is being tested for certification under the OECD code. Because this test requires a lot of cost and time to develop the ROPS and to produce test model, the OECD is discussing the introduction of virtual test using finite element analysis. In this study, the results were compared by conducting a strength test and finite element analysis applied with the OECD code to use it as a basic data for standardization of ROPS virtual test methods. It was confirmed that the results of the analysis of the bolts and plates of the coupling part and the folding part were more close to the physical test results than the rigid elements and constraints at the point of coupling the tractor and ROPS.

Purpose: This study aimed to quantitatively compare the stress sensitivity of cortical and cancellous bones under varying preload torques and loading directions in zirconia abutment implant systems by finite-element analysis. Methods: A three-dimensional finite-element model of a mandibular implant system was developed, comprising a zirconia abutment, a Ti-6Al-4V screw and fixture, and surrounding bone structures. The model assumed complete osseointegration and linear elastic properties. Three torque conditions (10, 20, and 30 N·cm) and two loading angles (30° oblique, 90° vertical) with a 175 N occlusal force were applied. To assess stress sensitivity, maximum principal stress was measured in the cortical and cancellous bones across all scenarios. Results: The cortical bone consistently exhibited higher absolute stress values than the cancellous bone. However, the cancellous bone showed a markedly greater increase in stress between 20 and 30 N·cm torque, particularly under oblique loading (30°), with the stress increasing by >59.2%. In contrast, the cortical bone demonstrated a more gradual and linear stress response. Both bone types showed intensified stress concentrations at high torque levels and under oblique loading, suggesting increased mechanical vulnerability in the cancellous bone. Conclusion: The cancellous bone is more sensitive to preload torque and loading direction changes than the cortical bone in zirconia abutment systems. This finding underscores the need for cautious torque applications and stress-distributing prosthetic designs, particularly in areas with poor bone quality.

Purpose: The purpose of this study was to evaluate the stability of abutment screws used with the zirconia fixture-based implant system and compare them with those used with the existing titanium fixture system via the finite element method. Methods: A single implant-supported restoration was designed for the finite element analysis. A universal analysis program was used to set 8 occlusal points along the direction to the long axis of the implant, and an occlusal load of 700 N was applied. Results: In all models (Zir and Ti-fixture model), the screw threads presented with the highest von Mises stress (VMS) values, whereas the head and end presented with the lowest VMS values. The VMS of the screw used in the zirconia-fixture model was 5.97% lower than that used in the titanium-fixture model (261.258 vs. 276.911 MPa, respectively) despite statistical significance. Furthermore, the zirconia fixture (352.912 MPa) had a higher stress value (8.42%) than the titanium fixture (332.331 MPa). In a completely tightened titanium fixture implant system, the stress was concentrated in the implant-abutment connection interface, the zirconia fixture presented with a stable stress distribution. Conclusion: Although the zirconia fixture demonstrated a high VMS value, owing to the stiffness and elasticity coefficients of the material, the stress generated in the abutment screws was similar in all models. In conclusion, the zirconia fixture-based implant system presented with a more stable stress distribution in the abutment screws than the titanium fixture-based implant system.

Purpose: This study aimed to analyze the stress distribution and deformation in implant abutments made from titanium (Ti-6Al-4V), zirconia, and polyetheretherketone (PEEK), including their screws and fixtures, under various loading conditions using finite element analysis (FEA). Methods: Three-dimensional models of the mandible with implant abutments were created using Siemens NX software (NX10.0.0.24, Siemens). FEA was conducted using Abaqus to simulate occlusal loads and assess stress distribution and deformation. Material properties such as Young’s modulus and Poisson’s ratio were assigned to each component based on literature and experimental data. Results: The FEA results revealed distinct stress distribution patterns among the materials. Titanium alloy abutments exhibited the highest stress resistance and the most uniform stress distribution, making them highly suitable for long-term stability. Zirconia abutments showed strong mechanical properties with higher stress concentration, indicating potential vulnerability to fracture despite their aesthetic advantages. PEEK abutments demonstrated the least stress resistance and higher deformation compared to other abutment materials, but offered superior shock absorption, though they posed a higher risk of mechanical failure under high load conditions. Conclusion: The study emphasizes the importance of selecting appropriate materials for dental implants. Titanium offers durability and uniform stress distribution, making it highly suitable for long-term stability. Zirconia provides aesthetic benefits but has a higher risk of fracture compared to titanium. PEEK excels in shock absorption but has a higher risk of mechanical failure compared to both titanium and zirconia. These insights can guide improved implant designs and material choices for various clinical needs.

This study was carried out to standardize the material properties of roll-over protective structure (ROPS) for agricultural tractor. The material properties which were obtained from stress-strain curve, a result of tensile test stress, were used to apply to the virtual test and varied from one production lot to the other and from one manufacturer to the other. And the finite element analysis was performed on the ROPS according to the OECD code. The results show that the load-displacement curves of virtual test were approximately equal to the actual test curves. The manufacturer or lot has been shown to have little effect on the properties of the material. Therefore, it is expected that the representative values that can be used in the finite element analysis can be determined by averaging the property values.

Purpose: This study aimed to comparatively evaluate the stress distribution of bones surrounding the implant system to which both titanium and polyetheretherketone (PEEK) abutments are applied using a three-dimensional finite element analysis. Methods: The three-dimensional implant system was designed by the computer-aided design program (CATIA; Dassault Systemes). The discretization process for setting nodes and elements was conducted using the HyperMesh program (Altair), after finishing the design of each structure for the customized abutment implant system. The results of the stress analysis were drawn from the Abaqus program (Dassault Systèmes). This study applied 200 N of vertical load and 100 N of oblique load to the occlusal surface of a mandibular first molar. Results: Under external load application, the PEEK-modeled dental implant showed the highest von Mises stress (VMS). The lowest VMS was observed in the Ti-modeled abutment screws. In all groups, the VMS was observed in the crestal regions or necks of implants. Conclusion: The bones surrounding the implant system to which the PEEK abutment was applied, such as the cortical and trabecular bones, showed stress distribution similar to that of the titanium implant system. This finding suggests that the difference in the abutment materials had no effect on the stress distribution of the bones surrounding implants. However, the PEEK abutments require mechanical and physical properties improved for clinical application, and the clinical application is thought to be limited.

Purpose: Zirconia is differentiated from other ceramics because of its high resistance to corrosion and wear, excellent flexural strength (900~1400 MPa), and high hardness. Dental zirconia with proven mechanical/biological stability is suitable for the manufacture of implants. However, there are limited in vivo studies evaluating stress distribution in zirconia compared with that in titanium implants and studies analyzing finite elements. This study was conducted to evaluate the stress distribution of the supporting bone surrounding zirconia and titanium implants using the finite element analysis method. Methods: For finite element analysis, a single implant-supported restoration was designed. Using a universal analysis program, eight occlusal points were set in the direction of the occlusal long axis. The occlusal load was simulated at 700 N. Results: The zirconia implant (47.7 MPa) von Mises stress decreased by 5.3% in the upper cortical bone compared with the titanium implant (50.2 MPa) von Mises stress. Similarly, the zirconia implant (20.8 MPa) von Mises stress decreased by almost 4% in the cancellous bone compared with the titanium implant (21.7 MPa) von Mises stress. The principal stress in the cortical and cancellous bone exhibited a similar propensity to von Mises stress. Conclusion: In the supporting bone, the zirconia implant is able to reduce bone resorption caused by mechanically transferred stress. It is believed that the zirconia implant can be a potential substitute for the titanium implant by reinforcing aesthetic characteristics and improving stress distribution.

척추경 나사못 시스템은 척추경 나사못, 강봉, 횡연결 기기로 구성되어 있으며, 척추경을 통해 안정성을 부여 할 수 있고 견고한 고정이 가능하기 때문에 퇴행성 추간판 탈출증 등에 사용된다. 척추경 나사못 시스템은 신경 손 상을 피할 수 있다는 장점이 있지만, 시술 부위의 운동을 제한함으로써 시술 및 인접 부위의 퇴행성을 가속화 시키 는 문제점이 있다. 이러한 문제점을 보완하고자 척추체의 시술 부위를 안정화시키며 유연하게 운동할 수 있는 반강 성 고정법 개념의 후방 유동적 추간체 고정재 제품이 최근 출시되고 있다. 척추경 나사못 시스템의 성능 평가에 관 한 국제 규격은 ASTM F1717이 있다. 이 규격은 척추체 절제술 모델에서 척추용 임플란트의 정적 및 동적 시험을 위 한 지그를 비롯한 실험 환경 및 시험방법을 제시하고 있으나, 시술 후 운동성 변화에 대해서 평가하는 시험방법에 대 해서는 제시되어 있지 않는 한계점이 있다. 따라서 본 연구에서는 유한 요소 분석을 이용하여 척추경 나사못 시스템 의 강봉 형태 및 횡연결 기기 삽입 유무에 따른 다양한 생리학적 하중 조건에서 요추부(L4-L5)의 운동성 변화를 분 석하고, 유한 요소 분석 방법이 성능 평가 등에 활용할 수 있는 가능성을 제시하고자 하였다.

The pedicle screw system consists of pedicle screws, steel rods and a transverse connecting device. It can be used for treatment of degenerative disc herniation because it can provide stability through two pedicles and can be firmly fixed. Although the pedicle screw system has the advantage of avoiding nerve damage, there is a problem of accelerating the degeneration of adjacent sites by limiting the movement of the operation site. To solve this problem, the semi-rigid fixation which can stabilize the operated site of t he vertebral body and flexibly move has been recently introduced. An international standard for performance evaluation of pedicle screw system is ASTM F1717. This standard describes an experimental environment and test methods including the jig for the static and dynamic testing of the spinal implant in the vertebral body resection model, but there is a limit to the test method for evaluating the change of ROM. In this study, we analyzed the changes of ROM in various physiological loading conditions according to the shape of the rods and the insertion of transverse connecting device using the finite element analysis. We proposed a possibility that the finite element analysis can be used for performance evaluation of spinal implants.

As the widespread adoption of autonomous vehicles is anticipated, a greater diversity of occupant postures is expected. However, current vehicle safety systems are not adequately designed to accommodate these varied postures, particularly relaxed seating positions, in which severe injuries have been reported during frontal collisions. Therefore, it is essential to investigate the biomechanical responses and injury tolerances of occupants in relaxed postures. In this study, the head kinematics and injury responses of the Hybrid-III and THOR anthropomorphic test devices, as well as the THUMS human body model, in a relaxed posture are analyzed using frontal impact sled simulations equipped with the sled system model developed in the previous study. The simulation results are evaluated through comparison with post-mortem human surrogate data. The findings of this study are expected to contribute to the fundamental design of new head restraint systems for human heads in autonomous vehicles.