scholarly journals Finite element analysis and approximate estimation of the cross coupling effect in fractured reservoirs

2003 ◽  
Vol 30 (14) ◽  
Author(s):  
Roland W. Lewis ◽  
William K. S. Pao ◽  
Xin-She Yang
2013 ◽  
Vol 838-841 ◽  
pp. 284-296
Author(s):  
Yu Hua Wang ◽  
Bei Bei Wang ◽  
Pei Chi ◽  
Jun Dong

The finite element analysis method was adopted to simulate the masonry wall strengthened with steel strips and was verified by comparing with test results. The influence rules of two factors including the cross sectional area of steel strips and vertical compression were investigated. The results show that, as for unreinforced masonry wall, the relationship of the shear capacity of unreinforced masonry wall and the vertical compressive strain is linear under lateral load; the speed of stiffness degeneration is accelerated after the peak point of the curves, but decrease with the increasing of lateral displacement. As for masonry wall strengthened with steel strips, the shear capacity increases significantly, and shows nonlinear relationship with the cross section area of the steel strips and vertical compression; ductility is improved. Finally, a computational formula of shear capacity based on a lot of parametric analysis is proposed to calculate the sectional dimension of steel strips, and it provides theoretical foundation for establishing thorough design method of masonry wall strengthened with steel strips.


2016 ◽  
Vol 26 (7) ◽  
pp. 1003-1027 ◽  
Author(s):  
Xianyan Wu ◽  
Qian Zhang ◽  
Bohong Gu ◽  
Baozhong Sun

This article reports the longitudinal compressive crashworthiness of three-dimensional four-step circular braided carbon/epoxy composite tubes at temperatures of 23, −50, and −100℃ under strain rate ranging from 340 to 760/s both experimentally and finite element analysis. The experimental results showed that the compression strength, stiffness, and specific energy absorption increased with the decrease in temperature and with the increase in strain rate. It also showed that, the compressive damage morphologies were sensitive to the change in temperature and strain rate. A coupled thermal-mechanical numerical analysis was conducted to find the thermo/mechanical coupling effect on the compressive crashworthiness of the three-dimensional composite tube. The temperature distributions in the braided preform and the resin during the impact compression were also calculated through finite element analysis. From the finite element analysis results, the inelastic heat generation was seen to be more in the preform than the matrix and its distribution and accumulation led to the damage progress along the loading direction.


2011 ◽  
Vol 194-196 ◽  
pp. 1900-1903
Author(s):  
Baek Il Bae ◽  
Hyun Ki Choi ◽  
Chang Sik Choi

The installation of new opening is necessary for remodeling project, house merging type. Current structural design code cannot provide the deterministic way for designing the shear walls with openings. So many engineers prefer to retrofit the perforated wall area for the structural safety. For the safe design of retroftitting, for the perforated structural walls, we carried out nonlinear finite element analysis to find the coupling effect of remaing walls. Specifically, many types of shapes were considered and various area of rectangular openings were analyzed. For the effective retrofitting, door shape and such area about 20% of wall is appropriate for retrofitting of reinforced concrete shearwalls.


2008 ◽  
Vol 2 (1) ◽  
Author(s):  
Milton E. Aguirre ◽  
Mary Frecker

A size and shape optimization routine is developed for a 1.0mm diameter multifunctional instrument for minimally invasive surgery. The instrument is a compliant mechanism capable of both grasping and cutting. Multifunctional instruments are expected to be beneficial in the operating room because of their ability to perform multiple surgical tasks, thereby decreasing the total number of instrument exchanges in a single procedure. With fewer instrument exchanges, the risk of inadvertent tissue trauma as well as overall surgical time and costs are reduced. The focus of this paper is to investigate the performance effects of allowing the cross-sectional area along the length of the device to vary. This investigation is accomplished by defining various cross-sectional segments in terms of parametric variables and optimizing the dimensions of the instrument to provide a sufficient opening of the forceps jaws while maintaining adequate cutting and grasping forces. Two optimization problems are considered. First, all parametric segments are set equal to one another to achieve size optimization. Second, each segment is allowed to vary independently, thereby achieving shape optimization. Large deformation finite element analysis and optimization are conducted using ANSYS®. Finally, prototypes are fabricated using wire EMD and experiments are conducted to evaluate the instrument performance. As a result of allowing the cross-sectional area to vary, i.e., conducting shape optimization, the forceps and scissors blocked forces increased by as much as 83.2% and 87%, respectively. During prototype evaluations, it is found that the finite element analysis predictions were within 10% of the measured tool performance. Therefore, for this application, it is concluded that performing shape optimization does significantly influence the performance of the instrument.


Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 850
Author(s):  
Juhong Han ◽  
Dingcheng Huang ◽  
Jingyu Chen ◽  
Xiaofang Lan

The effects of steel fiber length (lf = 30 mm, 40 mm, 50 mm and 60 mm) and coarse aggregate maximum size (Dmax = 10 mm, 20 mm, 30 mm and 40 mm) on fractural properties of steel fiber reinforced concrete (SFRC) was investigated. The results show that the fracture energy (Gf) of SFRC reaches its maximum when Dmax increases to 30 mm, and it increases first and then decreases as lf increases, but it still has a significant increase compared to the control concrete. The Gf ratio increases first and then decreases as the lf/Dmax increases. The Gf of the SFRC fracture surface follows the same trend as the fractal dimension. The rational range of the lf/Dmax is 2.5–4 for the considerable strengthening effect of steel fiber on fracture performances of concrete with the Dmax of 10 mm and 20 mm and 1.5–2.33 for that concrete with the Dmax of 30 mm and 40 mm. The finite element analysis results are compared with the experimental results, and the results show that the fracture process of the finite element model is consistent with the experiment.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Song-Jian Li ◽  
Ben-Chao Shi ◽  
Cheng-Long Liu ◽  
Yu-Bin Liu

Abstract Background Little information was obtained from the published papers about the kinematic coupling effect between tarsal bones during Ponseti manipulation. The aim was to explore the kinematic coupling effect of the joints around talus, to investigate the kinematic rhythm and coupling relationship of tarsal joints; to clarify the pulling effect on medial ligament of the ankle during the process of Ponseti manipulation. Methods The model of foot and ankle was reconstructed from the Chinese digital human girl No.1 (CDH-G1) image database. Finite element analysis was applied to explore the kinematic coupling effect of the joints around talus. The distal tibia and fibula bone and the head of talus were fixed in all six degrees of freedom; outward pressure was added to the first metatarsal head to simulate the Ponseti manipulation. Kinematic coupling of each tarsal joint was investigated using the method of whole model splitting, and medial ligament pulling of the ankle was studied by designing the model of medial ligament deletion during the Ponseti manipulation. Results All the tarsal joints produced significant displacement in kinematic coupling effect, and the talus itself produced great displacement in the joint of ankle. Quantitative analysis revealed that the maximum displacement was found in the joints of talonavicular (12.01mm), cuneonavicular (10.50mm), calcaneocuboid (7.97mm), and subtalar(6.99mm).The kinematic coupling rhythm between talus and navicular, talus and calcaneus, calcaneus and cuboid, navicular and cuneiform 1 were 1:12, 1:7, 1:2 and 1:1.6. The results of ligaments pulling showed that the maximum displacement was presented in the ligaments of tibionavicular (mean 27.99mm), talonavicular (21.03mm), and calcaneonavicular (19.18 mm). Conclusions All the tarsal joints around talus were involved in the process of Ponseti manipulation, and the strongest kinematic coupling effect was found in the joints of talonavicular, subtalar, calcaneocuboid, and cuneonavicular. The ligaments of tibionavicular, talonavicular, and calcaneonavicular were stretched greatly. It was suggested that the method of Ponseti management was a complex deformity correction processes involved all the tarsal joints. The present study contributed to better understanding the principle of Ponseti manipulation and the pathoanatomy of clubfoot. Also, the importance of cuneonavicular joint should be stressed in clinical practice.


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