Cracking Mechanism and Strengthen Method of Reinforced Concrete Hammerhead Piers

2013 ◽  
Vol 351-352 ◽  
pp. 1408-1414
Author(s):  
Guo Bin Tang ◽  
Tong Ning Wang ◽  
Feng Hu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Strength ◽  
Tensile Stress ◽  
Field Investigation ◽  
Element Analysis ◽  
Side Crack ◽  
Cracking Mechanism ◽  
Cracking Process ◽  
Strengthening Method

This paper indicates cracking mechanism and strengthening method of reinfoced concrete hammerhead piers. A field investigation phase has been undertaken in conjunction with analytical studies to model the cracking process. It is shown that the front cracks in the pier cap developed because the bending tensile stress far exceeds the tensile strength, while the side crack caused by none bursting reinforcement. Based on the analysis results, an internally prestressing approach is provided, and the retrofitting effect is verified by finite element analysis. Strengthening with internally prestressed tendons of bridge pier cap is proven to be a reliable and relatively easy-to-install technique.

Maximum Stress at Intersecting Bores of Pressurized Blocks

1994 ◽  
Author(s):  
Ajay Garg
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Stress ◽  
Element Model ◽  
Maximum Tensile Stress ◽  
Pressure Vessels ◽  
Experimental Results ◽  
Empirical Methods ◽  
Element Analysis ◽  
Matched Design

Abstract In high pressure applications, rectangular blocks of steel are used instead of cylinders as pressure vessels. Bores are drilled in these blocks for fluid flow. Intersecting bores with axes normal to each other and of almost equal diameters, produce stresses which can be many times higher than the internal pressure. Experimental results for the magnitude of maximum tensile stress along the intersection contour were available. A parametric finite element model simulated the experimental set up, followed by correlation between finite element analysis and experimental results. Finally, empirical methods are applied to generate models for the maximum tensile stress σ11 at cross bores of open and close ended blocks. Results from finite element analysis and empirical methods are further matched. Design optimization of cross bores is discussed.

scholarly journals A Finite Element Analysis and Cyclic Load Experiment on an Additional Transcortical-Type Hole Formed Around The Proximal Femoral Nail System’s Distal Locking Screw

2021 ◽  
Author(s):  
Hong Man Cho ◽  
Seung Min Choi ◽  
JiYeon Park ◽  
Young Lee ◽  
Jung Hyung Bae
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Stress ◽  
Intertrochanteric Fracture ◽  
Proximal Femoral Nail ◽  
Element Analysis ◽  
Distal Locking ◽  
Femoral Nail ◽  
Hole Model ◽  
Locking Screw

Abstract Background A complication associated with the distal locking screw used in the proximal femoral nail (PFN) system is the formation of accidental additional holes. We hypothesized that an increase in stress around additional holes is a relevant factor contributing to fractures. This study aimed to evaluate stress changes in the cortical bone around additional screw holes using finite element analysis. Methods Proximal femoral nail PFN antirotation (PFNA)-II (Synthes, Solothurn, Switzerland) was inserted into a femur model. An additional 4.9-mm transcortical hole was made either anteriorly (anterior hole model) or posteriorly (posterior hole model) to the distal locking screw. Finite element analysis was used to calculate compression, tension, and load limits to investigate stress around additional holes with respect to the direction of screw penetration and degree of osteoporosis. The results were then compared with those of mechanical testing. A 31A-21 type intertrochanteric fracture was applied. As a control group, a model without additional holes (no-hole model) was developed. Repeated load-loading tests were performed on 10 model bones per model group. Results Tensile stress was significantly greater in the no-hole model when additional screw holes were present, and the anterior hole showed a higher maximum stress value than the posterior hole did, suggesting that the anterior hole was more susceptible to fracture. The change in tensile stress first appeared in the hole around the lateral cortical bone and proceeded to the medial side. Biomechanical testing showed that fractures around the distal locking screw occurred in 0 cases of the no-hole, 10 of anterior hole, and 9 of the posterior hole models. Conclusions During PFN surgery for intertrochanteric fracture, holes with distal locking screws fixed and removed at the anterior and posterior of the nail can be a risk factor for fractures in the surrounding area.

Finite Element Analysis of Dynamic Splitting Tensile Mechanical Properties of Reinforced Concrete

2014 ◽  
Vol 941-944 ◽  
pp. 695-700
Author(s):  
Xiao Yan Song ◽  
Pei Wen Zhang
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Strength ◽  
Reinforced Concrete ◽  
Strain Rate ◽  
Failure Mode ◽  
Splitting Tensile Strength ◽  
Reinforcement Ratio ◽  
Element Analysis

Finite element analysis is carried out on the dynamic splitting tensile mechanical properties of reinforced concrete with LS-DYNA. The impact of strain rate and reinforcement ratio on the dynamic tensile strength and failure mode of reinforced concrete is considered in the calculation. The result shows that the form of reinforcement and reinforcement ratio has a greater impact on the failure mode and tensile strength of concrete. The dynamic splitting tensile strength of reinforced concrete has a certain strain rate effect and its splitting tensile strength increases with the strain rate; the splitting tensile strength of reinforced concrete also increases with its reinforcement ratio.

Simulation on the Thermal Stress of Super304H Oxidation Scale at 600°C

2014 ◽  
Vol 1065-1069 ◽  
pp. 1934-1938 ◽  
Author(s):  
Jun Wei Chen ◽  
Zhen Jiang ◽  
Hao Mu ◽  
Qiang Wan ◽  
Lei Hu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Stress ◽  
Tensile Stress ◽  
Oxide Layer ◽  
Cross Section ◽  
Geometric Model ◽  
Steam Oxidation ◽  
Element Analysis ◽  
Oxidation Scale

In this paper, based on the analysis of cross-section of steam oxidation of Super304H sample at 600°C, thermal stress contours were obtained by using finite element analysis through establishing geometric model and refine meshing. After extracting the stress in the interface of oxide layer and analyzing the thermal stress, it can be found that there exists compressive and tensile stress in the interface between substrate and scale, which is affected by the slope of the interface.

scholarly journals Investigations of Mechanical Properties of API P110 Steel Casing Tubes Operated in Deep-Sea Sour Condensate Well Conditions

2020 ◽  
Vol 27 (3) ◽  
pp. 121-129
Author(s):  
Yao Zilin ◽  
Wang Yu ◽  
Yang Xuefeng ◽  
Gao Anping ◽  
Zhang Rong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Strength ◽  
Yield Strength ◽  
Deep Sea ◽  
Performance Model ◽  
Continuous Change ◽  
Element Analysis ◽  
Equivalent Yield

AbstractDue to the complexity of the marine environment, in deep-sea drilling, all kinds of strings are corroded by different deep-sea conditions for a long time, accompanied by high temperature and high pressure, which lead to the continuous change of mechanical properties of materials. In order to solve the problem that the material mechanical parameters cannot be accurately described in the performance analysis of the casing, deep-sea simulated corrosion and material damage experiments of P110 material were carried out in this paper. Mass loss and tensile experiments on corrosion-damaged test pieces were conducted under different corrosion experimental periods. The changes in mechanical properties of the material were analyzed. Equations of the variation of the equivalent yield strength and the equivalent tensile strength were obtained. The results show that the equivalent yield strength and the equivalent tensile strength decrease with the increase of the weight loss rate. Based on the experimental results and finite element analysis, a method for establishing the material corrosion model was proposed in this paper. The deep-sea drilling corrosion performance model of P110 material was established, which greatly reduced the error caused by the material uniformity assumption in finite element analysis. This paper provides a theoretical basis for the analysis of reliability and life of P110 materials in wells.

scholarly journals Tensile strength and thermal cycle analysis of AA6061 friction weld joints with different diameters and various friction times

2021 ◽  
Vol 2 (12 (110)) ◽  
pp. 15-21
Author(s):  
Yudy Surya Irawan ◽  
Moch Agus Choiron ◽  
Wahyono Suprapto
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Strength ◽  
Thermal Cycle ◽  
Flash Temperature ◽  
Element Analysis ◽  
Infrared Thermometer ◽  
Circular Bar ◽  
Different Diameters ◽  
Friction Weld

The paper reports measurement of tensile strength and the thermal cycle of AA6061 aluminum alloy circular bar friction weld with different diameters and various friction times. A continuous drive friction welding (CDFW) of AA6061 was conducted to weld the AA6061 circular bar with different diameters of 30 mm for the rotating part and 15 mm for the stationary part. The CDFW process was carried out with the revolution speed of 1,600 rpm, the initial compressive force of 2.8 kN during the friction stage for various friction times of 10, 12, and 14 seconds, and an upset force of 28 kN for 60 seconds. The flash temperature was measured using a digital infrared thermometer gun. Computer simulation using the finite element method was also done by coupling transient thermal and static structural methods. The flash temperature becomes higher along with increasing friction time based on the digital infrared thermometer gun measurement and finite element analysis. The results of tensile strength testing show that the specimen with a friction time of 12 seconds has the highest tensile strength. Based on the hardness testing result, it is found that the specimen with a friction time of 10 seconds has higher hardness, but it has an incomplete joint flash so that the tensile strength is lower than that of the specimen with a friction time of 12 seconds. Besides, the hardness of the specimen with a friction time of 12 seconds is higher than that of the specimen with a friction time of 14 seconds. The flash size becomes bigger along with the increase of the friction time based on the macrostructure observation on the longitudinal section of the CDFW specimen. It is confirmed by the temperature measurement and finite element analysis that the specimen with a friction time of 12 seconds has heat input to form the CDFW joint that has a maximum tensile strength in the range of this study

Laser and plasma dental soldering techniques applied to Ti-6Al-4V alloy: Ultimate tensile strength and finite element analysis

2015 ◽  
Vol 113 (5) ◽  
pp. 460-466 ◽  
Author(s):  
Morgana G. Castro ◽  
Cleudmar A. Araújo ◽  
Gabriela L. Menegaz ◽  
João Paulo L. Silva ◽  
Mauro Antônio A. Nóbilo ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Element Analysis
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