Papers by Keyword: Axial Load

Abstract: In a nuclear power plant, the tubes array component that constitutes a cooling water heat exchanger is often subjected to cold and hot fluid flow impact, which are affected by axial stress due to thermal strain cause by these cold and hot flow impact. So, the dynamic characteristics of this tube would be changed significantly by this flow impact and even lead to failure. The axial load caused by thermal strain, the cold and hot flow impact, also markedly changes the dynamic characteristics of the tube.

Abstract: This paper analyzes stress distribution in a solid elliptical cross-section under axial load, bending moment, and torsional load, which are common in structural and mechanical engineering. The study aims to derive an explicit formula for von Mises stress as a function of cross-sectional coordinates, providing a unified measure to assess material failure under combined loads.

Abstract: Standard duplex stainless steel X2CrNiMoN22-5-3 is resistant to both, corrosion and mechanical stress, but corrosion fatigue (CF) lowers the lifetime expectancy in a geothermal environment such as the Northern German Basin. Laboratory experiments used the in-situ electrolyte at 369 K in a specifically designed corrosion chamber applying rotation bending cyclic load to failure. CF behaviour was compared to pure push-pull load. Corrosion kinetics are independent of the load applied. Failure is initiated by pits resulting in mechanical degradation. Increased thickness of the passivating layer surrounding pits enhances degradation or delamination. Also, sharp notches located along the pit edge increase notch effects and stress concentration consequently leading to fast crack propagation and early failure.

Abstract: The relationship between implant thread design and dental bone arguably has an influence on the distribution of bone stresses. However, the existing data on the influence of the thread profiles on bone stresses is considerably conflicting. For example, some studies concluded that thread shape has a substantial effect on the intensity of bone stresses, while others revealed that thread shape has no effect on the intensity of bone stresses. Accordingly, this study aims to computationally investigate and compare the effect of dental implant thread design on bone stresses under axial loading using a finite element analysis (FEA) approach. A geometrical model of V-thread and square thread implants, with a fixed thread pitch of 0.8 mm and a depth of 42 mm, and the surrounding bone was developed to assess the stresses generated within the implant components and bone structure under a 114 N axial load. The simulation is primarily concerned with the von Mises stresses within the implant components and the surrounding bone. The results demonstrate that the V-thread implant causes extremely high stress on the cortical and cancellous bones compared to the square thread implant. For example, the maximum stresses induced in the cortical bone are 195.3 MPa and 68.8 MPa, while the maximum stresses created in the cancellous bone are 19.7 Mpa and 2.2 Mpa in both designs, respectively. In addition, the cortical bone stresses substantially exceed the implant body stresses in both designs, with maximum stresses of 93.18 Mpa and 41 Mpa for V-thread and square-thread implants, respectively. However, the implant thread shape doesn’t affect the stress distribution in the abutment and screw. In general, the results show that implant thread design can result in featured mechanical stresses in the implant body and bone structure.

Abstract: Building collapses from the seismic pounding of two adjacent buildings have been found in many past earthquakes. For the two buildings with different story height, the pounding induces impact load and local stress at column mid-height where the provided column reinforcement is normally lesser than the column’s edge. This paper aims to investigate the impact responses of reinforced concrete columns with different axial load and shear capacity by using numerical simulation method. Sixteen reinforced concretes columns were subjected to an impact load created by dropping 300 kg hammer at the height of 1,200 mm above the mid-span of the column. Every specimen has an identical cross section of 220 mm by 220 mm, with 3,000 mm of clear span length. Both ends of the column were fully restrained. The magnitude of the axial load varies from 0% to 40% of the ultimate axial capacity of the concrete section. Shear reinforcement spacing varies from @200 mm to @60 mm. It is found that the axial loads have a great effect on the impact responses of the RC columns. The specimens with high axial load yield higher peak impact force value and less mid-span deflection. Shear cracks were observed on the specimens with low axial force, but the cracks were relatively decreased when increasing the axial load.

Abstract: This work is dedicated to an experimental research of strength and resistance characteristics of axially loaded concrete filled steel tube elements of self-stressing concrete, including high-performance concrete. Labcrete specimens of circular section 112 mm in diameter and 1000 mm in length were used in experiments. The research shows that the use of self-stressing concrete increased the strength of the specimens by approximately 10%, and enhanced elastic behavior limit by 20-33%. In the course of testing self-stressing concrete specimens, registered longitudinal deformations were within 0.52-0.75%. Analysis of the obtained results indicates a significantly greater case effect in the pre-stressed specimens. This effect is somewhat less pronounced in high-performance concrete specimens, yet still prominent.

Abstract: Aluminum tubes are efficient energy absorbing components and are widely used in the automobile industry. In the previous report, the authors investigated the influence of cross-sectional shape on axially compressed aluminum tube by numerical analysis. However, there are only a few reports on length of aluminum tube. This paper deals with the influence of axial length and reinforcing rib on dynamic axially compressed aluminum polygonal tube in order to obtain the basic data of buckling and impact resistance. A numerical analysis of the dynamic deformation process of the polygonal tube was made with a finite element method. The result shows that even if the axial length was changed, there was no difference in the trend of the load-displacement curve in each cross-sectional shape. However, the maximum load part on load-displacement curve was changed. The buckling was generated partially and the deformation was larger at the corners in each axial length and cross-sectional shape.

Abstract: Basic concept of structural design is to transmit the loading from superstructure to substructure. This idea normally required sound knowledge of structural design and rational engineering judgments. Recently, there have several techniques that can be utilized to determine the superstructure loading, such as finite element method and tributary area method. However, the compatibility of both methods in order to determine the loading from superstructure is prime important and has been investigated in this research framework. Axial loading, represented as products from dead load and service load, which are imposed on the top of slab is directly transmit to the column nearby and modelled through computer simulation. Models of slab were then varies and studies through comparison with broad dimensions of slab thickness, ranging in 100 mm to 600 mm. Results has shown the increasing of slab thickness will indirectly increases the rigidity characteristic of slab and potential to distribute the axial load equally for all column members. Axial load against slab thickness on corner, edge, center, outer and inner column demonstrated the incompatibility for both methods, finite element method and tributary area method in determining the axial loading from superstructure.

Abstract: Using the explicit finite difference code FLAC3D, the behavior of pile adjacent to braced excavation is investigated. The Modified-cam clay constitutive model was employed to model the non-linear stress-strain soil behavior, and the pile was assumed to have linear elastic behavior. The interface model incorporated in FLAC3D code was used to simulate the soil/pile contact, The built-in 'fish' language was used to calculate the data demanded. The pile response such as pile deflection, bending moment and lateral soil pressure were studied, and it is shown that the pile response is different from that caused by the excavations which are unstructted. In "standard" problem, the effect of different pile head constraints on the pile response was investigated, the effect of lateral displacement of the wall, distance from the excavation face, pile stiffness, pile length and axial load on the pile response are also investigated when the pile head is constrained from deflection. The research finding was compared with other published case history and reasonably good agreement was found between them.

Abstract: Beam-column joints can play a key role on the seismic behavior of reinforced concrete buildings. Until now studies and experimental investigations on this topic have been mainly focused on beam-column joints with stiff beams, i.e. beams with height larger than the thickness of the adjacent floor slab. However, especially in the European residential building stock, frame structures are often equipped with wide - therefore rather flexible - beams. However, not many studies have been devoted so far to this type of connection, therefore an experimental investigation on full scale beam-column joints with wide beam was planned at the University of Basilicata and is currently in progress. In the present paper the main results of two cyclic tests are reported and discussed specifically analyzing the role of the axial load applied to the column on the joint performances and damage mechanisms. Test results highlights that the axial load value has a significant influence of on deformation capacity and ductility behavior.