• Title/Summary/Keyword: material modeling

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Study on shear fracture behavior of soft filling in concrete specimens: Experimental tests and numerical simulation

  • Lei, Zhou;Vahab, Sarfarazi;Hadi, Haeri;Amir Aslan, Naderi;Mohammad Fatehi, Marji;Fei, Wu
    • Structural Engineering and Mechanics
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    • v.85 no.3
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    • pp.337-351
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    • 2023
  • In this paper, the shear behavior of soft filling in rectangular-hollow concrete specimens was simulated using the 2D particle flow code (PFC2D). The laboratory-measured properties were used to calibrate some PFC2D micro-properties for modeling the behavior of geo-materials. The dimensions of prepared and modeled samples were 100 mm×100 mm. Some disc type narrow bands were removed from the central part of the model and different lengths of bridge areas (i.e., the distance between internal tips of two joints) with lengths of 30 mm, 50 mm, and 70 mm were produced. Then, the middle of the rectangular hollow was filled with cement material. Three filling sizes with dimensions of 5 mm×5 mm, 10 mm×5 mm, and 15 mm×5 mm were provided for different modeled samples. The parallel bond model was used to calibrate and re-produce these modeled specimens. Therefore, totally, 9 different types of samples were designed for the shear tests in PFC2D. The shear load was gradually applied to the model under a constant loading condition of 3 MPa (σc/3). The loading was continued till shear failure occur in the modeled concrete specimens. It has been shown that both tensile and shear cracks may occur in the fillings. The shear cracks mainly initiated from the crack (joint) tips and coalesced with another one. The shear displacements and shear strengths were both increased as the filling dimensions increased (for the case of a bridge area with a particular fixed length).

Potential side-NSM strengthening approach to enhance the flexural performance of RC beams: Experimental, numerical and analytical investigations

  • Md. Akter, Hosen; Mohd Zamin, Jumaat;A.B.M. Saiful, Islam;Khalid Ahmed, Al Kaaf;Mahaad Issa, Shammas;Ibrahim Y., Hakeem;Mohammad Momeen, Ul Islam
    • Structural Engineering and Mechanics
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    • v.85 no.2
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    • pp.179-195
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    • 2023
  • The performance of reinforced concrete (RC) beam specimens strengthened using a newly proposed Side Near Surface Mounted (S-NSM) technology was investigated experimentally in this work. In addition, analytical and nonlinear finite element (FE) modeling was exploited to forecast the performance of RC members reinforced with S-NSM utilizing steel bars. Five (one control and four strengthened) RC beams were evaluated for flexural performance under static loading conditions employing four-point bending loads. Experimental variables comprise different S-NSM reinforcement ratios. The constitutive models were applied for simulating the non-linear material characteristics of used concrete, major, and strengthening reinforcements. The failure load and mode, yield and ultimate strengths, deflection, strain, cracking behavior as well as ductility of the beams were evaluated and discussed. To cope with the flexural behavior of the tested beams, a 3D non-linear FE model was simulated. In parametric investigations, the influence of S-NSM reinforcement, the efficacy of the S-NSM procedure, and the structural response ductility are examined. The experimental, numerical, and analytical outcomes show good agreement. The results revealed a significant increase in yield and ultimate strengths as well as improved failure modes.

A case study of protecting bridges against overheight vehicles

  • Aly, Aly Mousaad;Hoffmann, Marc A.
    • Steel and Composite Structures
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    • v.43 no.2
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    • pp.165-183
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    • 2022
  • Most transportation departments have recognized and developed procedures to address the ever-increasing weights of trucks traveling on bridges in a service today. Transportation agencies also recognize the issues with overheight vehicles' collisions with bridges, but few stakeholders have definitive countermeasures. Bridges are becoming more vulnerable to collisions from overheight vehicles. The exact response under lateral impact force is difficult to predict. In this paper, nonlinear impact analysis shows that the degree of deformation recorded through the modeling of the unprotected vehicle-girder model provides realistic results compared to the observation from the US-61 bridge overheight vehicle impact. The predicted displacements are 0.229 m, 0.161 m, and 0.271 m in the girder bottom flange (lateral), bottom flange (vertical), and web (lateral) deformations, respectively, due to a truck traveling at 112.65 km/h. With such large deformations, the integrity of an impacted bridge becomes jeopardized, which in most cases requires closing the bridge for safety reasons and a need for rehabilitation. We proposed different sacrificial cushion systems to dissipate the energy of an overheight vehicle impact. The goal was to design and tune a suitable energy absorbing system that can protect the bridge and possibly reduce stresses in the overheight vehicle, minimizing the consequences of an impact. A material representing a Sorbothane high impact rubber was chosen and modeled in ANSYS. Out of three sacrificial schemes, a sandwich system is the best in protecting both the bridge and the overheight vehicle. The mitigation system reduced the lateral deflection in the bottom flange by 89%. The system decreased the stresses in the bridge girder and the top portion of the vehicle by 82% and 25%, respectively. The results reveal the capability of the proposed sacrificial system as an effective mitigation system.

A machine learning-based model for the estimation of the critical thermo-electrical responses of the sandwich structure with magneto-electro-elastic face sheet

  • Zhou, Xiao;Wang, Pinyi;Al-Dhaifallah, Mujahed;Rawa, Muhyaddin;Khadimallah, Mohamed Amine
    • Advances in nano research
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    • v.12 no.1
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    • pp.81-99
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    • 2022
  • The aim of current work is to evaluate thermo-electrical characteristics of graphene nanoplatelets Reinforced Composite (GNPRC) coupled with magneto-electro-elastic (MEE) face sheet. In this regard, a cylindrical smart nanocomposite made of GNPRC with an external MEE layer is considered. The bonding between the layers are assumed to be perfect. Because of the layer nature of the structure, the material characteristics of the whole structure is regarded as graded. Both mechanical and thermal boundary conditions are applied to this structure. The main objective of this work is to determine critical temperature and critical voltage as a function of thermal condition, support type, GNP weight fraction, and MEE thickness. The governing equation of the multilayer nanocomposites cylindrical shell is derived. The generalized differential quadrature method (GDQM) is employed to numerically solve the differential equations. This method is integrated with Deep Learning Network (DNN) with ADADELTA optimizer to determine the critical conditions of the current sandwich structure. This the first time that effects of several conditions including surrounding temperature, MEE layer thickness, and pattern of the layers of the GNPRC is investigated on two main parameters critical temperature and critical voltage of the nanostructure. Furthermore, Maxwell equation is derived for modeling of the MEE. The outcome reveals that MEE layer, temperature change, GNP weight function, and GNP distribution patterns GNP weight function have significant influence on the critical temperature and voltage of cylindrical shell made from GNP nanocomposites core with MEE face sheet on outer of the shell.

Study of Modeling for Stock Food Material with Location Movement by the Communication Signal System

  • Kim, Jeong-Lae;Kim, Jung-Yun;Rha, Young-Ah
    • International Journal of Advanced Culture Technology
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    • v.9 no.4
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    • pp.409-416
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    • 2021
  • We are invented the movement composition technique that is to check the food adjacent-package status of the wireless-management movement monitoring level (WMMML) on the movement monitoring communication system. The movement monitoring level condition by the movement monitoring communication system is formatted with the adjacent-package system. As to inspection a wireless RFID of the wireless RFID, we are found of the movement value with wireless RFID by the adjacent upper take form. The concept of movement monitoring level is formatted the reference of wireless-management level for composition signal by the movement package communication system. Further symbolizing a food composition of the WMMML of the medium-minimum in terms of the adjacent-package communication system, and the movement wireless RFID package that was the movement value of the far composition of the Mo-MMCS-FA-φMED-MIN with 5.80±1.20 units, that was the movement value of the convenient composition of the Mo-MMCS-CO-φMED-MIN with 4.06±(-0.04) units, that was the movement value of the flank composition of the Mo-MMCS-MO-φMED-MIN with 0.91±0.07 units, that was the movement value of the vicinage composition of the Mo-MMCS-VI-φMED-MIN with 0.18±(-0.03) units. The adjacent package will be to look into at the food ability of the adjacent-package communication system with wireless RFID by the movement monitoring level on the WMMML that is supply the wireless communication by the movement monitoring level system. We will be possible to make effort of a communication system by the management signal and to put to use of the delivery data of RFID level by the delivery system.

Development of a Custom-Made Dress Form for Draping Based on 3D Handheld Scanners and 3D Printing Technology (3D 핸디형 스캐너와 3D 프린팅 기술 기반 드레이핑용 커스텀 메이드 드레스폼 개발)

  • Ryu, Eun Joo;Song, Hwa Kyung
    • Fashion & Textile Research Journal
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    • v.24 no.4
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    • pp.451-459
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    • 2022
  • This study aimed to develop a a custom-made dress form for draping using a live model's 3D body scan obtained from an entry-level 3D handheld scanners, 3D modeling software and 3D printing technology. A female subject was recruited whose body size fell under the normal (N) body shape criteria suggested by KS K 0051. First, the handheld scanner reduced the length of the legs in scanning, but most of the scanning operations between the neck and crotch levels were conducted accurately. Therefore, this study was designed to develop a torso dress form. The full body 3D scan was edited into a torso shape using ZBrush® software. Using Rhinoceros® and Materialise's Magics software, a 3D body scan was modeled so that the user could fit two types of mannequin stands (one with a neck fixation from above and one with an insert from below) to the dress form. The body scan was divided into 9 pieces to fit the printable size of the Stratasys 3D printer Fortus 250mc, and the cross-sectional distance from the center to the periphery was downsized by 2 mm. After outputting the dress form scan file with a 3D printer, the dress form was manufactured by the first covering it with a 4 oz nonwoven pad and the second covering with a single jersey material.

Application of Finite Element Analysis for Structural Stability Evaluation of Modern and Contemporary Sculptures: 'Eve 58-1' by Man Lin Choi

  • Kwon, Hee Hong;Shin, Jeong Ah;Cho, Nam Chul
    • Journal of Conservation Science
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    • v.38 no.4
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    • pp.277-288
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    • 2022
  • '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.

A Study on Structural-Thermal-Optical Performance through Laser Heat Source Profile Modeling Using Beer-Lambert's Law and Thermal Deformation Analysis of the Mirror for Laser Weapon System (Beer-Lambert 법칙을 적용한 레이저 열원 프로파일 모델링 및 레이저무기용 반사경의 열변형 해석을 통한 구조-열-광학 성능 연구)

  • Hong Dae Gi
    • Journal of Aerospace System Engineering
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    • v.17 no.4
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    • pp.18-27
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    • 2023
  • In this paper, the structural-thermal-optical performance analysis of the mirror was performed by setting the laser heat source as the boundary condition of the thermal analysis. For the laser heat source model, the Beer-Lambert model considering semi-transparent optical material based on Gaussian beam was selected as the boundary condition, and the mechanical part was not considered, to analyze the performance of only the mirror. As a result of the thermal analysis, thermal stress and thermal deformation data due to temperature change on the surface of the mirror were obtained. The displacement data of the surface due to thermal deformation was fitted to a Zernike polynomial to calculate the optical performance, through which the performance of the mirror when a high-energy laser was incident on the mirror could be predicted.

Application of Patient-Specific 3D-Printed Orthopedic Splint for Bone Fracture in Small Breed Dogs

  • Kwangsik Jang;Eun Joo Jang;Yo Han Min;Kyung Mi Shim;Chunsik Bae;Seong Soo Kang;Se Eun Kim
    • Journal of Veterinary Clinics
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    • v.40 no.4
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    • pp.268-275
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    • 2023
  • In this paper, we designed 3D-printed orthopedic splint models for patient-specific external coaptation on fracture healing and analyzed the stability of the models through finite element method (FEM) analysis under compressive load conditions. Polylactic acid (PLA) and acrylonitrile-butadiene-styrene (ABS) based 3D splint models of the thicknesses 1, 3, 5 and 7 mm were designed, and Peak von Mises stress (PVMS) and maximum displacement (MD) of the models were analyzed by FEM under compressive loads of 50, 100, 150, and 200 N. The FEM results indicated that PVMS and MD values, regardless of material, had a negative correlation with the thickness of the models and a positive correlation with the compressive load. There was a risk of splint deformation under conditions more extreme than 100 N with 5 mm thickness. For successful clinical application of 3D-printed orthopedic splints in veterinary medicine, it is recommended that the splint should be produced not less than 5 mm thickness. Also, it is expected to be stable when the splint is applied to situations with a compressive load of 100 N or less. There is an advantage of overcoming the limitations of the existing bandage method through 3D-printing technology as well as verifying the stability through 3D modeling before application. Such 3D printing technology will be widely used in veterinary medicine and various fields as well as orthopedics.

Adding AGC Case Studies to the Educator's Tool Chest

  • Schaufelberger, John;Rybkowski, Zofia K.;Clevenger, Caroline
    • International conference on construction engineering and project management
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    • 2022.06a
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    • pp.1226-1236
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    • 2022
  • Because students majoring in construction-related fields must develop a broad repository of knowledge and skills, effective transferal of these is the primary focus of most academic programs. While inculcation of this body of knowledge is certainly critical, actual construction projects are complicated ventures that involve levels of risk and uncertainty, such as resistant neighboring communities, unforeseen weather conditions, escalating material costs, labor shortages and strikes, accidents on jobsites, challenges with emerging forms of technology, etc. Learning how to develop a level of discernment about potential ways to handle such uncertainty often takes years of costly trial-and-error in the proverbial "school of hard knocks." There is therefore a need to proactively expedite the development of a sharpened intuition when making decisions. The AGC Education and Research Foundation case study committee was formed to address this need. Since its inception in 2011, 14 freely downloadable case studies have thus far been jointly developed by an academics and industry practitioners to help educators elicit varied responses from students about potential ways to respond when facing an actual project dilemma. AGC case studies are typically designed to focus on a particular concern and topics have thus far included: ethics, site logistics planning, financial management, prefabrication and modularization, safety, lean practices, preconstruction planning, subcontractor management, collaborative teamwork, sustainable construction, mobile technology, and building information modeling (BIM). This session will include an overview of the history and intent of the AGC case study program, as well as lively interactive demonstrations and discussions on how case studies can be used both by educators within a typical academic setting, as well as by industry practitioners seeking a novel tool for their in-house training programs.

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