The Research of the Stress Test Technology on Bridge Type Grab Ship Unloader

2013 ◽  
Vol 631-632 ◽  
pp. 1017-1021
Author(s):  
Cheng Zhong He ◽  
Han Dong Liu
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Stress Test ◽  
Maximum Tensile Stress ◽  
Safety Performance ◽  
Normal Operation ◽  
Maximum Compressive Stress ◽  
Test Technology ◽  
Bridge Type ◽  
Maintenance And Inspection

The safety performance of bridge type grab ship unloaders are the main factors in the normal operation of a bulk cargo wharf. This article made a research of the stress test technology on the use of safety assessment on the structure of the bridge type grab ship unloader, through the dynamic stress test of ship unloader key parts of the structure under the use of the condition, analysis bridge type grab ship unloader safety performance is at ordinary times and maintenance and inspection needs to focus on the dangerous site.Stress test shows that the Maximum compressive stress is Point 7, its maximum dynamic compressive stress is 82.5MPa; while the maximum tensile stress occurs at point 11, its maximum dynamic tensile stress of 72.5MPa. After 17 years used, The force main parts (except former trolleys) of the ship unloader are basically the same as its design value.

Convective Heat Transfer Steady Thermal Stress in a Ceramic/FGM/Metal Composite EFBC Plate with Temperature-Dependent Material Properties

2009 ◽  
Vol 79-82 ◽  
pp. 1363-1366 ◽  
Author(s):  
Yang Jian Xu ◽  
Dai Hui Tu
Keyword(s):  
Thermal Stress ◽  
Tensile Stress ◽  
Compressive Stress ◽  
Material Properties ◽  
Composite Plate ◽  
Maximum Tensile Stress ◽  
Metal Composite ◽  
Ceramic Surface ◽  
Temperature Dependent ◽  
Maximum Compressive Stress

A NFE model is constructed to analyze the convective heat transfer steady thermal stress in a ceramic/FGM/metal composite EFBC plate with temperature-dependent material properties. Based on thermoelasticity theory, we derive the NFE basic equation of heat conduction of the plate. We present a Sinpson method for the solution of steady thermal stress formulas of the composite plate. Using FORTRAN language we design the calculation software. From numerical calculation, when , T0=300K, Ta=500K and Tb=1 650K, the stress distributions in the plate were obtained. The results are as follows. With the increase of the FGM gradient layer thickness, the stress distribution is more reasonable, and the largest tensile stress of the EFBC composite plate reduces by 59.6%. With the increase of M, the stress change increases obviously in metal and ceramic layers, and the thermal compressive stress on the ceramic surface reduces by 78.1%. With the increase of porosity, the change of stress at the bonding interfaces increases, and the thermal compressive stress on the surface of ceramics reaches the maximum, and the thermal tensile stress on the surface of metal reaches the maximum too. Compared with , when , the tensile stress on the metal surface reduces by 91.3%, and the maximum compressive stress on the surface of ceramics increases 4.55 times. Compared with the nongraded two-layered ceramic/metal composite plate, the thermal stress of ceramic/FGM/metal composite EFBC plate is very gentle, and the maximum tensile stress reduces by 62.94%. When we consider the temperature-dependent material properties, the stress in graded three-layered composite plate becomes small obviously, and the maximum tensile stress in the plate reduces by 36.74%, and the maximum compressive stress on the ceramic surface reduces by 31.4%. The model can effectively analyze the thermal stresses and effect factors in a ZrO2/FGM/Ti-6Al-4V composite plate. The results provide the foundations of theoretical calculation for the design and application of the composite plate.

scholarly journals Analysis on accumulated deformation and stress of the steel roof of Beijing Opera House during construction

2021 ◽  
Vol 2045 (1) ◽  
pp. 012014
Author(s):  
L L Wu ◽  
G Gao ◽  
B R Ye ◽  
H D Zhang ◽  
Q Lu
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Vertical Displacement ◽  
Maximum Tensile Stress ◽  
Design Model ◽  
Construction Process ◽  
Maximum Compressive Stress ◽  
Finite Element Software ◽  
Stress And Deformation ◽  
Steel Roof

Abstract This paper aims to study the stress and deformation of large steel structure buildings in the actual construction process. Midas Gen finite element software is used to simulate and analyze the whole construction process of the curved reticulated shell roof, the peripheral steel columns and the permanent support. The stress and deformation results of the structure in the final construction state are compared with those in the design state under one-time loading. The results show that, in the final construction state, the maximum tensile stress and the maximum compressive stress are 1.9 times and 2.0 times of that in the design state under one-time loading respectively, which is very significant. When the design model is loaded with weight at one time, the maximum tensile stress and the maximum compressive stress of the structure both appear near the opening of the steel roof, while in the final construction state, the maximum tensile stress of the structure appears near the boundary frame beam, and the maximum compressive stress appears on the main ridge beam. The maximum vertical displacement of the structure in the final construction state is 2.0 times of that when the design model is loaded at one time. The maximum vertical displacement of the design state appears near the opening of the steel roof, while the maximum vertical displacement of the structure in the final construction state appears on the main ridge beam. In view of the above, the effective guidance for the construction of steel roof structure is provided in this paper to ensure the safety of the structure.

scholarly journals Field Tests on the Stress Characteristics of Enriched Water Tunnel Invert

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Mingqing Du ◽  
Xiang Li ◽  
Xuchun Wang ◽  
Hongwei Teng ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Theoretical Basis ◽  
Field Tests ◽  
Maximum Tensile Stress ◽  
Water Tunnel ◽  
Maximum Compressive Stress ◽  
Steel Bars ◽  
Floor Heave ◽  
Groundwater Level Changes

To monitor the changes in the force of the tunnel invert steel bars after the groundwater level changes, field tests were performed to accurately and comprehensively characterize the stress acting on the rebar of a tunnel invert. Changes in stress and temperature were monitored for two layers of rebar (upper and lower) in an actual tunnel invert during its repair. The results showed that the changes in stress followed different paths for the upper and lower layers. After the groundwater is replenished, the maximum tensile stress of the rebar was 17.3 MPa, and the maximum compressive stress was 120 MPa. Major changes in stress were observed 2–6 days after rain. Based on this, the seepage path of groundwater is analyzed. During this period, the compressive stress increased threefold, and the tensile stress increased 9.5-fold. The rebar stress in the tunnel invert followed a Gaussian distribution after stabilizing. Four phases of stress progression are identified and discussed. The results can provide data support and theoretical basis for the treatment of invert floor heave in enriched water tunnel.

Heating Steady Thermal Stress in a Composite EFBF Plate Made of Ceramic/FGM/Metal Considered Temperature Dependency

2009 ◽  
Vol 417-418 ◽  
pp. 537-540 ◽  
Author(s):  
Yang Jian Xu ◽  
Dai Hui Tu
Keyword(s):  
Thermal Stress ◽  
Tensile Stress ◽  
Compressive Stress ◽  
Composite Plate ◽  
Maximum Tensile Stress ◽  
Metal Composite ◽  
Temperature Dependency ◽  
Stress Distributions ◽  
Maximum Compressive Stress ◽  
Layered Ceramic

A NFE model is constructed to analyze the heating steady thermal stress in a ceramic/FGM/metal composite EFBF plate considered temperature dependency. From numerical calculation, when T0=Ta=300K and Tb=1 000K, the stress distributions in the plate were obtained. The results are as follows. With the increase of the FGM thickness, the stress distribution is more reasonable, and the largest tensile stress reduces by 45.64%. With the increase of M, the stress change increases obviously, and the compressive stress on the surface of ceramics reduces by 56.0%. Compared with A=0, the compressive stress of A=3.99 on the surface of metal increases by 94.2%, and the stress on the surface of ceramics changes from compressive stress to tensile stress. When T0=300K, Ta=700K, compared with Tb=1 050K, when Tb=1 800K, the compressive stress on the surface of metal increases 13.62 times, and the maximum compressive stress on the surface of ceramics increases 5.22 times. Compared with the two-layered ceramic/metal composite plate, the stress of ceramic/FGM/metal composite EFBF plate is very gentle, and the maximum tensile stress reduces by 44.2%. Compared with constant material properties, the maximum compressive stress on the surface of metal considered temperature dependency reduces by 59.1%. The results provide the foundations of theoretical calculation for the design and application of the composite plate.

Mechanical Behavior of Segmented Lining Structure of Tunnel under Acting Ground Fractures in Xi’an Zone

2011 ◽  
Vol 261-263 ◽  
pp. 1778-1783
Author(s):  
Sheng Jun Shao ◽  
Fang Tao She ◽  
Juan Fang
Keyword(s):  
Tensile Stress ◽  
Mechanical Behavior ◽  
Compressive Stress ◽  
Three Dimensional ◽  
Vertical Displacement ◽  
Maximum Tensile Stress ◽  
Internal Force ◽  
Subway Tunnel ◽  
Lining Structure ◽  
Pass Through

Xi’an ground fracture, caused by the extraction of groundwater and the movement of fault under soil strata, is a geo-hazard. The movement of ground fracture originates the uneven settlement of upward block and downward block. In Xi’an ground fracture region, the segmented lining structure was adopted in subway tunnel to pass through the ground fracture, so as to adapt for the uneven settlement. Three-dimensional elastic-plastic finite difference method was applied to simulate the initial lining structure, second segmented lining structure, surrounding soils and ground fracture. The horizontal and vertical displacement of segmented lining structure, surrounding soils pressure and internal force of segmented lining structure in subway tunnel were analyzed by the calculation results. The knowledge on mechanical behavior of segmented lining structure passing through an active ground fracture and surrounding soils was shown as following. The relative vertical displacement between segmented lining structure sects beside the ground fracture increases remarkably with the movement of ground fracture, and the segmented lining structure located in upward displaceent block near ground fracture originates notable rotary. Tension or compression deformation occured in the deformation joint between adjacent segmented lining structures near the ground fracture.There was a significant change in the contact pressure of the first sect of lining structure in the upward displace block. Under the same uniform settlement at the bottom of upward diaplacement block, the relativly vertical displacemtn on the surfaceof ground fracture strata without tunnel equals 50cm, but the relativly vertical displacement between adjacent segmented lining structure at ground fracture is 18.2cm on the design level of arch top of lining strcutre. the maximum tensile stress of segmented lining structure is 2.02MPa, the maximum compressive stress of segmented lining is 3.49MPa. In conclusion, segmented lining structure can adapts to the uneven settlement caused by the movement of ground fracture. Though maximum tensile and compressive stress of sengmented lining structure passing through the active ground fracture is bigger than the general lining structure located in soils strata without the ground fracture, the segmented lining structure constructed by the steel fibre concrete can bear with the maximum tensile stress.

scholarly journals Reliability Analysis of Resultant Stress for Unsymmetrical Columns for Stress Follow Exponential Distribution

2019 ◽  
Vol 8 (6S3) ◽  
pp. 1334-1337
Keyword(s):  
Tensile Stress ◽  
Reliability Analysis ◽  
Compressive Stress ◽  
Probabilistic Approach ◽  
Bending Stress ◽  
Maximum Compressive Stress ◽  
Eccentric Load ◽  
Component Reliability ◽  
Parameter Values ◽  
Resultant Stress

When a body is subjected to eccentric loads, the direct stress as well as bending stress is produced. Resultant stress is obtained by adding these two stresses. In this paper, probabilistic approach has been made for designing the structure of unsymmetrical column by finding suitable parameters length of outer square and length of a hole and eccentric load of the column to get the specified reliability of the structure of a body or component. Reliability analysis has been done at the point of maximum compressive stress occurred and at the point of minimum tensile stress occurred. Reliability computations have been obtained for changing the various parameter values. It is observed from the computations that Reliability of the component when compressive stress occurs at the edge AB increases with increasing of length of outer square, decrease of load, decrease of length of hole and increasing of eccentricity. Reliability of the component when tensile stress occurs at the edge CD increases with decrease of length of outer square increasing the length of a hole, decreases the load and decrease of eccentricity

Crack Resistance of Concrete with Incorporation of Light-Burnt MgO

2010 ◽  
Vol 168-170 ◽  
pp. 1348-1352
Author(s):  
Xia Chen ◽  
Hua Quan Yang ◽  
Shi Hua Zhou ◽  
Jian Jun Yan
Keyword(s):  
Crack Resistance ◽  
Compressive Stress ◽  
Stress Test ◽  
Cementitious Materials ◽  
Maximum Temperature ◽  
Test Machine ◽  
Cracking Resistance ◽  
Maximum Compressive Stress ◽  
Cracking Tendency ◽  
Cracking Stress

The advanced Temperature and Stress Test Machine was introduced to evaluate the cracking resistance of concrete with inclusion of light-burnt MgO under full restraint by tracking thermal and deformation development. Results showed that light-burnt MgO being incorporated ranging between 4 per cent and 6 per cent by mass of cementitious materials was beneficial to increase the maximum compressive stress and cracking stress of concrete by 0.37MPa and 0.2MPa on average respectively. The maximum temperature was slightly reduced from 59.8°C to 66.2°C while cracking temperature was significantly decreased from 0.8°C to minus 5.6°C. Sensitive anti-cracking coefficient F was forwarded to assess the early cracking tendency of concrete and in general, inclusion of 4 per cent light-burnt MgO with activity of 109s was rated the best in crack resistance.

Steady Thermal Stresses in a Ceramic/FGM/Metal Composite EFBC Plate under Convective Heat Transfer Boundary

2010 ◽  
Vol 150-151 ◽  
pp. 239-242
Author(s):  
Dai Hui Tu ◽  
Yang Jian Xu ◽  
Xiao Li Zhou
Keyword(s):  
Heat Transfer ◽  
Thermal Stress ◽  
Tensile Stress ◽  
Convective Heat Transfer ◽  
Compressive Stress ◽  
Metal Surface ◽  
Composite Plate ◽  
Metal Composite ◽  
Stress Distributions ◽  
Maximum Compressive Stress

The steady thermal stress distributions and effect factors in a ceramic/FGM/metal composite EFBC plate considered constant material properties under convective heat transfer boundary were investigated by the FEM and the Sinpson method. From numerical calculation, when , T0=300K, Ta=400K and Tb=1 400K, the stress distributions in the plate were obtained. The results are as follows. With the increase of the FGM layer thickness, the stress distribution in the composite plate is more reasonable. Compared with M=0.2, when M=5, the compressive stress on the ceramic surface reduces by 10.2%, and the tensile stress on the metal surface reduces by 21.7%. With the increase of A, the variations of thermal stress curves become big. Compared with A=0, when A=3.99, the tensile stress on the metal surface increases by 198.0%, and the maximum compressive stress on the surface of ceramics increases by 66.0%. Compared with the mutation of thermal stress at the cohesive interface of ceramic / metal two-layered composite plate, the thermal stress of ceramic/FGM/metal composite plate is very gentle. Compared with , when , the maximum tensile stress on the metal surface increases 1.44 times, and the maximum compressive stress on the surface of ceramics increases 1.50 times. The results provide the foundations of theoretical calculation for the design and application of the composite plate.

Instability Analysis of the Bipolar Plate for Welding Fuel Cell

2012 ◽  
Vol 152-154 ◽  
pp. 568-573
Author(s):  
Yu Xin Yao ◽  
Chun Yuan Shi
Keyword(s):  
Fuel Cell ◽  
Stress Distribution ◽  
Tensile Stress ◽  
Compressive Stress ◽  
Thin Plate ◽  
Bipolar Plate ◽  
Maximum Compressive Stress ◽  
Heating And Cooling ◽  
Instability Theory ◽  
The Difference

The instability of the bipolar plate for welding fuel cell was analyzed taking the bipolar plate as thin plate. The minimum compressive stress is calculated based on thin plate instability theory caused by longitudinal compressive stress. The simplified thermal stress distribution function is determined using the analytical solution of the plane heat conduction equation. The maximum compressive stress is determined through the analysis of the longitudinal stress distribution of the cross section passing through the solder point during heating and cooling process. The results are used to obtain the pre-tensile stress controlling the instability of the bipolar plate for welding fuel cell, and the minimum pre-tensile stress is the difference between the maximum compressive stress and the minimum compressive stress as the thin plate loses instability.

Steady Thermal Stress in a Ceramic/FGM/Metal Composite EFBC Plate Considered Temperature Dependency

2010 ◽  
Vol 177 ◽  
pp. 231-234
Author(s):  
Yang Jian Xu ◽  
Dai Hui Tu ◽  
Jian Hui Jia
Keyword(s):  
Thermal Stress ◽  
Tensile Stress ◽  
Compressive Stress ◽  
Metal Surface ◽  
Material Properties ◽  
Metal Composite ◽  
Temperature Dependency ◽  
Stress Distributions ◽  
Maximum Compressive Stress ◽  
Fgm Layer

The steady thermal stress distributions and effect factors in a ceramic/FGM/metal composite EFBC plate with temperature-dependent material properties during heating process were investigated by the NFEM and the Sinpson method. From numerical calculation, when T0=Ta=300K and Tb=1 300K, the stress distributions in the plate were obtained. The results are as follows. With the increase of the FGM layer thickness, the stress distribution in the composite plate is more reasonable. Compared with M=0.1, when M=10, the compressive stress on the ceramic surface increases by 9.0%, and the tensile stress on the metal surface reduces by 17.9%. With the increase of FGM layer porosity, the variations of thermal stress curves become big. Compared with A=0, when A=3.99, the tensile stress on the metal surface increases by 65.5%, and the maximum compressive stress on the surface of ceramics reduces by 27.5%. Compared with the results of constant material properties, when we consider the temperature dependency of the material properties, the maximum tensile stress on the surface of metal in the plate reduces by 30.1%, and the maximum compressive stress on the surface of ceramics in the plate reduces by 9.49%. Compared with the nongraded two-layered plate, the tensile stress at middle of the graded three-layered composite EFBC plate reduces by 53.5%. When T0=300K, Ta=700K, compared with Tb=1 050K, when Tb=1 800K, the tensile stress on the surface of metal increases 563MPa, and the maximum compressive stress on the surface of ceramics increases 7.24 times.

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