Troy Myers¹, Michael A. Sutton^1,*, Hubert Schreier², Alistair Tofts², Sreehari Rajan Kattil¹

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.2, pp. 1263-1298, 2024, DOI:10.32604/cmes.2024.048743 - 20 May 2024

Abstract To compare finite element analysis (FEA) predictions and stereovision digital image correlation (StereoDIC) strain measurements at the same spatial positions throughout a region of interest, a field comparison procedure is developed. The procedure includes (a) conversion of the finite element data into a triangular mesh, (b) selection of a common coordinate system, (c) determination of the rigid body transformation to place both measurements and FEA data in the same system and (d) interpolation of the FEA nodal information to the same spatial locations as the StereoDIC measurements using barycentric coordinates. For an aluminum Al-6061 double edge More >

Chengbao Hu^1,2,3, Shilin Gong^4,*, Bin Chen^1,2,3, Zhongling Zong⁴, Xingwang Bao⁵, Xiaojian Ru⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 997-1015, 2024, DOI:10.32604/cmes.2024.048640 - 16 April 2024

Abstract Strain localization frequently occurs in cohesive materials with friction (e.g., composites, soils, rocks) and is widely recognized as a fundamental cause of progressive structural failure. Nonetheless, achieving high-fidelity simulation for this issue, particularly concerning strong discontinuities and tension-compression-shear behaviors within localized zones, remains significantly constrained. In response, this study introduces an integrated algorithm within the finite element framework, merging a coupled cohesive zone model (CZM) with the nonlinear augmented finite element method (N-AFEM). The coupled CZM comprehensively describes tension-compression and compression-shear failure behaviors in cohesive, frictional materials, while the N-AFEM allows nonlinear coupled intra-element discontinuities More >

Jiaqi Wu¹, Li Zhuo^1,*, Jianliang Pei¹, Yao Li², Hongqiang Xie¹, Jiaming Wu¹, Huaizhong Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.1, pp. 621-645, 2024, DOI:10.32604/cmes.2024.046398 - 16 April 2024

Abstract The surrounding geological conditions and supporting structures of underground engineering are often updated during construction, and these updates require repeated numerical modeling. To improve the numerical modeling efficiency of underground engineering, a modularized and parametric modeling cloud server is developed by using Python codes. The basic framework of the cloud server is as follows: input the modeling parameters into the web platform, implement Rhino software and FLAC^3D software to model and run simulations in the cloud server, and return the simulation results to the web platform. The modeling program can automatically generate instructions that can run… More >

Chenxi Xiu^1,2,*, Xihua Chu²

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.3, pp. 2305-2338, 2024, DOI:10.32604/cmes.2023.030194 - 15 December 2023

Abstract This paper presents a micromechanics-based Cosserat continuum model for microstructured granular materials. By utilizing this model, the macroscopic constitutive parameters of granular materials with different microstructures are expressed as sums of microstructural information. The microstructures under consideration can be classified into three categories: a medium-dense microstructure, a dense microstructure consisting of one-sized particles, and a dense microstructure consisting of two-sized particles. Subsequently, the Cosserat elastoplastic model, along with its finite element formulation, is derived using the extended Drucker-Prager yield criteria. To investigate failure behaviors, numerical simulations of granular materials with different microstructures are conducted using… More >

D.S.Liu¹, C.L.Hsu^1,2

CMC-Computers, Materials & Continua, Vol.40, No.3, pp. 165-178, 2014, DOI:10.3970/cmc.2014.040.165

Abstract To ensure the reliability of microelectronics packages, the high strain rate deformation behavior of the solder joints must be properly understood. Accordingly, the present study proposes a hybrid experimental / numerical method for determining the optimal constants of the Johnson-Cook (J-C) constitutive model for 96.5Sn-3Ag-0.5Cu (SAC305) solder alloy. In the proposed approach, FEM simulations based on the J-C model are performed to describe the load-time response of an SAC305 ball solder joint under an impact velocity of 0.5 m/s. The optimal values of the constitutive model are then determined using an iterative Genetic Algorithm approach More >

Shaw-Jyh Shin¹, Chen-Hung Huang², Y.C. Shiah³

CMES-Computer Modeling in Engineering & Sciences, Vol.40, No.1, pp. 83-104, 2009, DOI:10.3970/cmes.2009.040.083

Abstract Owing to the CTE (Coefficient of Thermal Expansion) mismatch among solder joints, IC (Integrated Circuit) chip, and PCB (Printed Circuit Board), electronic packages shall experience fatigue failure after going though a period of thermal cycling. As a major means to enhance the reliability of the solder joints, underfill is often dispensed to fill the gap between the die and the substrate. This study aims at investigating how the underfill may affect the thermal fatigue life of WLCSP (Wafer Level Chip Scale Package) by means of FEA (finite element analysis). In this study, the thermal fatigue More >

Dyi-Cheng¹, Syuan-Yi Syong¹

CMC-Computers, Materials & Continua, Vol.13, No.3, pp. 191-200, 2009, DOI:10.3970/cmc.2009.013.191

Abstract Finite element simulations are performed to investigate the plastic deformation behavior of Ti-6Al-4V titanium alloy during its indirect extrusion through a four-hole die. The simulations assume the die, mandrel and container to be rigid bodies and ignore the temperature change induced during the extrusion process. Under various extrusion conditions, the present numerical analysis investigates the effective stress and profile of product at the exit. The relative influences of the friction factors, the temperature of billet and the eccentricity of four-hole displacement are systematically examined. The simulations focus specifically on the effects of the friction factor, More >