scholarly journals Active-Side Calculation Method for a Backhoe Hydraulic Excavator with Incomplete Digging Resistance in a Normal State

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Zhigui Ren ◽  
Junli Wang ◽  
Jin Chen ◽  
Junfeng Zhang ◽  
Jurong Liu ◽  
...  
Keyword(s):  
Normal State ◽  
Calculation Method ◽  
Tangential Force ◽  
Bending Moment ◽  
Reference List ◽  
Cylinder Pressure ◽  
Measured Stress ◽  
Motion Parameters ◽  
Working Device ◽  
Digging Resistance

The digging resistance in a normal state is the key to excavator design and automated excavation. It is difficult to accurately predict, simulate, or directly measure the digging resistance in a normal state due to uncertainties in the soil properties and excavation parameters. In this paper, a research idea is proposed that uses the working device as the entry point to indirectly calculate the digging resistance in a normal state by measuring the motion parameters and the cylinder pressure intensity. Based on the rule of combination for spatial force systems, a method for combining and projecting the system of the digging resistance is proposed in which the system is projected as six parts, and the tangential force, normal force, and bending moment in the plane of symmetry of the working device are the objects of the solution to avoid redundant equations. Based on kinematics and dynamics models of the excavator and the force and moment equilibrium conditions of the working device, equations for the active-side calculation of the incomplete digging resistance are derived. Based on these equations, the motion parameters of the working device and data on the cylinder pressure intensity obtained by measurement are used to calculate the incomplete digging resistance. The validation scheme and process proposed use the incomplete digging resistance as the external load to obtain the simulated stress of the working device through transient analysis. The simulated stress and the measured stress corresponding to the position of the measurement point are extracted and compared. The results show that there is a difference in the size of the numerical value between the simulated and measured stress, but the variation law is highly consistent, which validates the calculation method. In this paper, an active-side calculation method is provided for the incomplete digging resistance in a normal state without considering the soil-tool interaction relationships, which lays a theoretical foundation for the study of the digging resistance characteristics in a normal state, as well as excavator design and automated excavation.

scholarly journals Modeling of the limiting digging force of hydraulic excavator based on resistance characteristics

Mechanika ◽  
2019 ◽  
Vol 25 (5) ◽  
pp. 357-362
Author(s):  
Zhigui REN ◽  
Junli WANG ◽  
Zhihong ZOU ◽  
Yanyan WANG ◽  
Haojie ZHU
Keyword(s):  
Tangential Force ◽  
Bending Moment ◽  
Resistance Coefficient ◽  
Hydraulic Excavator ◽  
Moment Coefficient ◽  
Resistance Moment ◽  
Constraint Inequalities ◽  
Comparative Results ◽  
Digging Resistance ◽  
Digging Force

Based on the resistance characteristics, a model of theoretical  digging force was proposed in this paper, taking the tangential force, the normal force, and the bending moment into account simultaneously. Utilizing the relation among the normal resistance, the resistance moment, and the tangential resistance in practical digging process, three independent unknown quantities are transformed into only one variable. Afterwards, according to different digging patterns and complete machine limiting conditions, this research derived the constraint inequalities of the limiting digging force (LDF) and established the calculation models for LDF. Then, based on the value distribution laws of the digging resistance coefficient and the resistance moment coefficient, the calculation process and corresponding method of LDF under a given digging posture were obtained. Taking the digging resistance obtained by testing for 35 t hydraulic excavator with backhoe attachment as the reference, this paper compared the calculation results of the theoretical digging force for complete machine with those of the LDF model proposed in this research. The comparative results indicate that the LDF is consistent with the fact that the theoretical digging force is larger than or at least equal to the actual digging resistance. So, the LDF can exactly show the real limiting digging ability of the excavator more accurately. In this way, it can provide basis for mechanism optimization, structural strength design, trajectory planning, and control automation of the excavator.

Numerical Analysis on the Influence of Joints Inclination on the Characteristics of Deformation and Stability of Tunnel

2013 ◽  
Vol 790 ◽  
pp. 299-305
Author(s):  
Xiao Song Tang ◽  
Yong Fu Wang ◽  
Ying Ren Zheng
Keyword(s):  
Stability Analysis ◽  
Numerical Analysis ◽  
Calculation Method ◽  
Research Result ◽  
Bending Moment ◽  
Surrounding Rock ◽  
Interface Element ◽  
Tunnel Stability ◽  
Stability Of Surrounding Rock ◽  
The Stability

The paper adopts the interface element to simulate the joints so as to systematically and quantitatively study the deformation around tunnel, the mechanic state of lining and the stability under different inclining angles of joints. The result shows that the deformation around tunnel deteriorates mainly along the joint during the inner convergence effects of surrounding rock. When the inclining angle α=45°, the deformation around the tunnel is most serious, followed by that when α=90°, α=60°, α=30° and α=0°. At the same time, the influence of inclining angle on the distribution of the axial force of lining is comparatively small. But the distribution of bending moment and shear change obviously where the joints penetrate the tunnel. The tunnel stability of surrounding rock is the poorest when α=90° and the tunnel is most stable when α=0°. The stability of surrounding rock changes little when α is between 30° and 60°. The research result provides an effective calculation method for the forecast of deformation, the design of structure and the stability analysis of jointed tunnel. It is also helpful for the monitoring of construction and calculation of jointed tunnel in the future.

Resistance Analysis and Experiment of Excavator during Digging Operation

2012 ◽  
Vol 446-449 ◽  
pp. 2750-2754
Author(s):  
Li Da Liao ◽  
Qing Hua He ◽  
Da Qing Zhang ◽  
Hai Hua Zheng
Keyword(s):  
Inclination Angle ◽  
Dynamic Process ◽  
Empirical Equation ◽  
Hydraulic Cylinder ◽  
Resistance Test ◽  
Cylinder Pressure ◽  
Resistance Analysis ◽  
Tension Sensor ◽  
The Relationship ◽  
Digging Resistance

To research the actual resistance for excavator in digging process, the relationship between manipulator motion, cylinder pressure and digging resistance was analyzed. On this basis, the equation for calculating digging resistance of excavator was proposed. By using tension sensor, a digging resistance test was done under the actual digging movement environment. And the obtained inclination angle and hydraulic cylinder signal data were imported into digging resistance calculation equation to get a calculation resistance. After comparing the calculation resistance with the tension sensor readings, the following conclusions can be derived: this calculation equation can reflect effectively the size and dynamic process of actual resistance during digging operation, and it can describe the instantaneous changes and impact status of real resistance much better can the empirical equation in which the resistance is directly proportional to the digging depth.

scholarly journals The Calculation Method on the Bending Moment of a Battered Pile Induced by Ground Settlement

1987 ◽  
Vol 27 (2) ◽  
pp. 75-84 ◽  
Author(s):  
Satoru Sato ◽  
Fumihiko Iwashita ◽  
Hiroshi Ohmori
Keyword(s):  
Calculation Method ◽  
Bending Moment ◽  
Ground Settlement

Thermoelastic Modeling of Rotor Response With Shaft Rub

2010 ◽  
Vol 77 (6) ◽  
Author(s):  
S. Ziaei-Rad ◽  
E. Kouchaki ◽  
M. Imregun
Keyword(s):  
Friction Coefficient ◽  
Critical Speed ◽  
Normal Force ◽  
Contact Point ◽  
Tangential Force ◽  
Bending Moment ◽  
Contact Forces ◽  
Mass Unbalance ◽  
Deceleration Rate ◽  
The Time Domain

This paper studies the effects of shaft rub on a rotating system’s vibration response with emphasis on heat generation at the contact point. A 3D heat transfer code, coupled to a 3D vibration code, was developed to predict the dynamic response of a rotor in the time domain. The shaft bow is represented by an equivalent bending moment and the contact forces by rotating external forces. The seal ring is modeled as a linear spring, which exerts a normal force to the rotor. The tangential force is then calculated as the product of the normal force with the friction coefficient. Stable or unstable spiraling and oscillating modes were seen to occur in well defined shaft speed zones. In the main, for the configurations studied, the shaft vibration was found to be unstable for speeds below the first critical speed and stable for speeds above the first critical speed. Limit cycle behavior was observed when the phase angle between the unbalance force and the response was around 90 deg. The vibration behavior with rub during startup and shutdown was studied by considering the effects of acceleration/deceleration rate, friction coefficient, and mass unbalance. It was found that friction coefficient and increasing mass unbalance amplified the rub effects while acceleration/deceleration rate reduced it.

scholarly journals Dynamic Analysis of Working Device of Excavator under Limit Digging Force

2021 ◽  
Author(s):  
Xiaojun Wang ◽  
Haoran Sun ◽  
Minghao Feng ◽  
Zhigui Ren ◽  
Jurong Liu
Keyword(s):  
External Load ◽  
Structural Strength ◽  
Tangential Force ◽  
Coupling Model ◽  
Point Force ◽  
Strength Analysis ◽  
Force Model ◽  
Hinge Point ◽  
Working Device ◽  
Digging Force

AbstractIn order to more accurately analyze the dynamic characteristics of the working device of the hydraulic excavator. The load changes on the two digging trajectories were calculated and analyzed by using the limit digging force model and the theoretical digging force model, respectively. The rigid-flexible coupling model of the working device was established in ADAMS. Taking the limit digging force (LDF) and the theoretical digging force (TDF) as the external load of the working device, the dynamic simulation of the hinge force of the working device in the two trajectories was carried out, and the structural strength analysis of the bucket was carried out by using ANSYS. The results show that the tangential force of the LDF is generally larger than that of the TDF, the hinge point force of the working device changes dynamically with the external load of the tooling, and the influence of the LDF on the hinge point force is greater than that of the TDF. When the LDF is taken as the external load, the structural strength of the bucket meets the operational requirements.

Calculation Method of the Residual Capability of Damaged Warships

2008 ◽  
Author(s):  
Huilong Ren ◽  
Chenfeng Li ◽  
Guoqing Feng ◽  
Hui Li
Keyword(s):  
Mechanical Properties ◽  
Statistical Characteristic ◽  
Residual Strength ◽  
Calculation Method ◽  
Bending Moment ◽  
Ship Hull ◽  
Strength Assessment ◽  
Smith Method ◽  
Longitudinal Bending ◽  
Characteristic Values

The residual capability of damaged warships is one of the important aspects of its residual strength assessment. The calculation method of ultimate longitudinal bending moment was based on the Smith method. Then, a method to calculate the statistical characteristic values of residual capability of damaged warships was presented, in which some uncertainties, such as the size of broken holes caused by weapons, material mechanical properties of the steel and the size of structures, etc, were considered. The ultimate longitudinal bending moment of Reckling No.23 model was calculated and compared with the result from the literature, the result is quite satisfactory. With a warship as an example, the statistical characteristic values of residual capability of the damaged ship hull were calculated, and some factors which may evidently affect the residual capability were investigated.

A Method of Calculation on the Deformation of Column Piles in Deep Foundation Pit

2013 ◽  
Vol 291-294 ◽  
pp. 1131-1134
Author(s):  
Lin Na Sun ◽  
Yan Liu ◽  
Li Ming Zhang
Keyword(s):  
Calculation Method ◽  
Bending Moment ◽  
Practical Case ◽  
Vertical Deformation ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Method Of Calculation ◽  
Overall Stability

During excavation of deep foundation pits, the effects of vertical deformation on column piles are often neglected while those uplifts may lead to destruction of internal supports. The factors leading to the column piles' vertical deformation mainly include basal uplift and vertical loads. In this paper, the causation and mechanism of the column piles' uplift are discussed. The influence of the additional bending moment due to the column piles' vertical deformation on the overall stability of the founda-tion pit is analyzed. A calculation method of the permissible value of vertical deformation is present¬ed. The method is verified by a practical case to be feasible.

The Principle and Calculation Method of Carbon Fiber Reinforcement for Tunnels and Underground Structures

2011 ◽  
Vol 94-96 ◽  
pp. 1247-1251
Author(s):  
Hong Ke Pan ◽  
Jiang Chun Hu ◽  
Lin De Yang
Keyword(s):  
Carbon Fiber ◽  
Bearing Capacity ◽  
Calculation Method ◽  
Underground Structure ◽  
Fiber Reinforcement ◽  
Bending Moment ◽  
Design Calculation ◽  
Underground Engineering ◽  
Single Section ◽  
Carbon Fiber Reinforcement

There will emerge cracks or damage due to the action of rock pressure or its own shortcomings and low strength for the lining structure in tunnel or underground engineering, especially at the places of excessive bending moment and tensile stress because of bias pressure where concrete will be pull apart for the deficiency of strength even to cause leakage and durability insufficient. Conventional maintenance and reinforce methods are time-consuming and laborious, and the effect is also not ideal. It is simple, timesaving and having a significant and lasting effect to use carbon fiber reinforcement method. This paper studied structure’s failure mechanism and on the basis of that the principle of fiber-plate reinforcement from the angle of structural plastic development, then studied the improvement of structure’s mechanical character and the change of design calculation method for single section of underground structure with carbon fiber plates by using the research method of plane-strain. At the same time, the typical model of integral failure for single section was analyzed and the calculation method and formulae of bearing capacity and reinforcing steel bars were deduced, which remedied the shortfall in the design specification for concrete structure. In the end, by comparing the calculation results of structure with fiber plates and that with not fiber plates based on engineering example, the conclusion that structure’s bearing capacity and capability of resistance to deformation had obvious improvement was obtained.

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