Limit equilibrium stability analysis of slopes under external loads

Two calculation modes for the effect of external load on slope stability, i.e., mode I in which the external load is thought to act on slope surface, and mode II in which the external load is thought to act on slip surface along the force action line, were considered. Meanwhile, four basic distribution patterns of external load were used, of which complex external loads could be composed. In analysis process, several limit equilibrium methods, such as Swedish method, simplified Bishop method, simplified Janbu method, Spencer method, Morgenstern-Price(M-P) method, Sarma method, and unbalanced thrust method, were also adopted to contrast their differences in slope stability under the external load. According to parametric analysis, some conclusions can be obtained as follows:(1) The external load, with the large magnitude, small inclination angle, and acting position close to the slope toe,has more positive effect on slope stability;(2) The results calculated using modes I and II of external load are similar, indicating that the calculation mode of external load has little influence on slope stability;(3) If different patterns of external loads are equivalent to each other, their slope stability under these external loads are the same, and if not, the external load leads to the better slope stability,as action position of the resultant force for external load is closer to the lower sliding point of slip surface.

External blast flow field evolution and response mechanism of single-layer reticulated dome structure

Single-layer reticulated dome structure are commonly high-profile building in the public and can be attractive targets for terrorist bombings,so the public can benefit from enhanced safety with a stronger understanding of the behavior of single-layer reticulated dome structure under explosion.This paper investigates the fluid-structure interaction process and the dynamic response performance of the singlelayer reticulated dome under external blast load.Both experimental and numerical results shown that structural deformation is remarkably delayed compared with the velocity of blast wave,which advises the dynamic response of large-span reticulated dome structure has a negligible effect on the blast wave propagation under explosion.Four failure modes are identified by comparing the plastic development of each ring and the residual spatial geometric of the structure,i.e.,minor vibration,local depression,severe damage,and overall collapse.The plastic deformation energy and the displacement potential energy of the structure are the main consumers of the blast energy.In addition,the stress performance of the vertex member and the deep plastic ratio of the whole structure can serve as qualitative indicators to distinguish different failure modes.

External versus Internal Loads of Nutrients of an Urban Eutrophic Tropical Reservoir （Southeastern Brazil）

This study aimed to evaluate the external and internal fluxes of nutrients of an urban eutrophic reservoir （lbirit6 reservoir, SE-Brazil）. External loads were estimated in the tributaries （Pintados and Ibirit6 creeks） through nutrient concentrations and discharge measurements. Using Fick＇s law, internal loads were estimated in the reservoir from fluxes across sediment-water interface from nutrient concentration gradients between the pore water and the water. The Ibirit6 creek （urban sewage recipient） contributes with 72%-47% of ammonium （NH4^＋） and 100%-8% of SRP （soluble reactive phosphorus） of the total quantity entering the reservoir, whereas the Pintados creek （oil refinery effluent recipient） contributions are 20%-19% and 44%-100%, respectively. Despite the high external loads （130 and 2.2 ton-yr^-1 of NH4＋ and SRP, respectively）, internal loads （average flux of 120 and 2 mg·cm^-2yr^-1, respectively） correspond to 25% of the total external loads which may sustain a high productivity in the reservoir for a long time even if the external loads are controlled. The stocks of ammonium and SRP of the interstitial water （100 cm of sediment） would be released to the water in six years and five months, respectively, The release time would be extremely larger （〉 3,000 years） considering the stocks of total N and bioavailable P.

Methods for measuring and calculating the external load of powered supports

Taking the chock shield supports as the object of study, methods formeasuring and calculating the external load of powered supports were discussed. Selecting the angleparameters as variables, the simple formulae of interactive computation with respect to the workangles of a powered support were deduced and verified by an example. Furthermore, the formulaedetermining the magnitude, direction and action point of the external load were put forward. Theinvestigation results have provided a sound basis for the software design of the intelligentinstrument for load measuring of powered supports.

The Choice of Model of External Load in Problem of Synthesis of Adequate Mathematical Description

The problem of mathematical simulation of motion of dynamic systems characteristics and their coincidence with real experimental data which correspond to these characteristics is investigated in this paper. Mathematical description of process will be named as adequate mathematical description if the results of mathematical simulation by the help of this description coincide with experiment with inaccuracy of initial data. The synthesis of such description is very important at mathematical modeling and forecast of motion of real physical phenomena. The specified problem is still poorly investigated and hardly adapted to formalization. The requirements to the adequate mathematical description of dynamic system are considered for the case when mathematical description of dynamic systems is represented by linear system of the ordinary differential equations. In this paper the mathematical model of process is given a priori with inexact parameters and then the models of external loads are being determined for which the results of simulation coincide with experiment. The methods of obtaining of the steady models of external loads are suggested. The example of the adequate description construction of the main mechanical line dynamics of rolling mill is given.

Effect of pipe installation and external load on buried steel pipe responses:Experimental and numerical investigations

During pipe installation,compacting soil at pipe sides causes an initial pipe deformation which is known as the"peaking"effect.However,in conventional pipe design codes,only pipe deformation caused by vertical overburden is considered while the"peaking"effect is ignored.In this study,a full-scale test was conducted on a Grade X52 steel pipe with a diameter of 600 mm to investigate the impacts of both soil compaction and vertical overburden on pipe deformation.Soil compaction and external load were found to elongate and shorten the vertical pipe diameter,respectively.The"peaking"effect was observed during the installation procedure accompanied by the highest pipe stress measured at the pipe crown.Then,a two-dimensional finite element model was created and validated based on the calculated pipe stresses from the experimental study.A parametric study was performed thereafter to numerically study the impacts of soil water content,pipe wall thickness,compaction pressure,and lift thickness on pipe responses due to soil compaction and external load.An increase in the"peaking"effect is observed with increasing soil water content and compaction pressure,while an increase in pipe wall thickness or lift thickness would cause a decrease in the"peaking"effect.

No external load measurement strategy for micro thermoelectric generator based on high-performance Si_(1-x-y)Ge_(x)Sn_(y) film

In this study,a micro in-plane p-type thermoelectric generator(TEG),which consists of thin-film Si_(1-x-y)Ge_(x)Sn_(y) ternary alloy semiconductor on insulator,is developed to make efficient use of waste heat such as human body.A power factor value as high as 1095 mWm^(-1) K^(-2) had been achieved using Bion implanted and short-term rapid thermal annealing(RTA)process.In addition,a measuring scheme for micro TEG without external load resistance was designed.In one measuring session,multiple parameters can be measured.The micro single-arm TEG prepared by semiconductor process can output 0.29 nW power at a temperature difference of 15 K,and a cross-sectional power density has reached up to 0.58 mW/cm^(2),which is a superior value for wearable device.The findings of this study have important reference value for wearable device performance improvement and output power measuring of micro TEG.

Design and modeling of a novel soft parallel robot driven by endoskeleton pneumatic artificial muscles

Owing to their inherent great flexibility, good compliance, excellent adaptability, and safe interactivity, soft robots have shown great application potential. The advantages of light weight, high efficiency, non-polluting characteristic, and environmental adaptability provide pneumatic soft robots an important position in the field of soft robots. In this paper, a soft robot with 10 soft modules, comprising three uniformly distributed endoskeleton pneumatic artificial muscles, was developed. The robot can achieve flexible motion in 3D space. A novel kinematic modeling method for variable-curvature soft robots based on the minimum energy method was investigated, which can accurately and efficiently analyze forward and inverse kinematics. Experiments show that the robot can be controlled to move to the desired position based on the proposed model. The prototype and modeling method can provide a new perspective for soft robot design, modeling, and control.