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1

Environmental Assessment of Energy Dissipation over Submerged Dams Using MATLAB Simulation

Shehab Fatin M.

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 3

1--8

EN

In this study, a MATLAB simulation model was developed for the purpose of calculating the energy dissipation of runoff over submersible dams. A laboratory model of a submersible dam with standard dimensions was used, and two angles of inclination of the dam surface 16° and 24.5° were used downstream. In the laboratory work, the discharge and water depth were measured, in addition to the length of the hydraulic jump and the distance from the source, and by using the basic flow equations, the percentage of flow energy dissipation was calculated for both models, and the discharges were counted. The values of the Froude number ranged from 3.612 to 10.784. A simulation model was built in the MATLAB program using the basic equations of flow, finding the values of energy dissipation percentage and comparing them with the laboratory results. Then drawing the relationships between each of the discharge (Q), energy dissipation percentage (E%), Froude number (Fr), hydraulic jump length (Lj), and the distance of the hydraulic jump from the submerged dam (Dj). The numerical and experimental data have been compared, and it has been determined that there is an acceptable agreement between them. The results also showed the efficiency of using the MATLAB simulation method to obtain accurate and fast results.

2

CFD Analysis of the Effects of Compound Downstream Slope on Flow Over the Spillway

Jahad Udai A., Chabuk Ali, Alabas Mohammed A., Mahmoud Ammar S., Al-Ansari Nadhir, Laue Jan

Journal of Ecological Engineering

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2023

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Vol. 24, nr 11

274--286

EN

The volume of the stilling basin can be reduced, energy can be dissipated, and floods can be contained with the help of spillways. The aim of this Computational Fluid Dynamics (CFD) study is to investigate how compound slopes change water flows through spillways. To measure turbulence, the Realizable k-ε model was used, and the multiphase volume of fluid (VOF) method was utilized to determine where air and water meet. Five models of spillways with different slopes (normal slope (MS1) = 30°, compound slope(MS2 and MS3) = 20°/39°, and compound slope (MS4 and MS5) = 39°/20°) were modelled and simulated using the ANSYS Fluent software to determine their flow characteristics. Numerical simulation results were compared to experimental results, and it was found that the CFD model captured the key flow aspects accurately. The numerical model carefully observes the several flow patterns (nappe, transition, and skimming) that emerged owing to variations in slope and geometry. When it comes to dissipating energy, models with a compound slope (39°/20°) do the best. When compared to the normal slope model (30°) with a step size of 10, the increase in energy dissipation is 14%. According to the findings, the TKE (turbulent kinetic energy) was elevated by the compound slope. The results of this research show that the spillway can be operated effectively and reliably under a wide range of flow conditions, fulfilling an important goal of the project.

3

Effect of strain rate on static elastic response of glass-polyester composite. Part 1, Description of test method

Kozioł Mateusz

Composites Theory and Practice

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2023

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R. 23, nr 1

22--29

EN

This paper is the first of two parts of a pioneering study to evaluate the effect of the strain rate of a GFRP laminate on the stress response. The assessment concerns the elastic range of deformation only. The publication contains the assumptions and methodological description of the conducted experiments. The non-destructive bending tests and the methodology for determining the modulus of elasticity and the energy of the load-unload cycle are presented in detail. The full set of test results is presented in the appendix. The results and conclusions are discussed in the second part of the study, which is a separate publication.

4

Effect of strain rate on static elastic response of glass-polyester composite. Part 2, Analysis of experimental results

Kozioł Mateusz, Latusek Szymon

Composites Theory and Practice

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2023

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R. 23, nr 1

44--49

EN

This paper is the second part of a study aimed at evaluating the influence of the strain rate of a plain weave GFRP laminate in a non-destructive static three-point bending test on the stress response of the material. It was found that the stress level during the entire course of the deflection rises with the increase in the strain rate. The relative change in the stress level is comparable for the 0/90 and 45/-45 samples. As the loading speed increases, the elastic modulus of the material also grows. For an increment in the strain rate from 1.11·10–3 to 5.57·10–1 1/s, the increase is 10% for the 0/90 samples and 17.7% for the 45/-45 samples. The dependence of the modulus on the strain rate is logarithmic. Based on the theoretical analysis, the cause of the observed effects of the strain rate on the material response was attributed to the viscoelastic behawior of the matrix (cured polymer resin) and the viscoelastic behavior of the system of fibers at the level of the laminate mesostructure.

5

Polyurethane shape memory polymer: structure characterization and estimation of energy storage and dissipation during the tension process

Staszczak Maria, Gradys Arkadiusz, Golasiński Karol, Pieczyska Elżbieta A.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 6

art. no. e147343

EN

Shape memory polymers (SMP) are new multifunctional materials raising increasing interest in various functional applications. Among them, polyurethane shape memory polymers (PU-SMP) are particularly attractive due to their combination of shape memory, high strength and biocompatible properties. Developing new applications for PU-SMP requires comprehensive research on their characteristics. This work involved investigating the structure and mechanical behavior as well as characterizing the energy storage and dissipation of a thermoplastic PU-SMP with a glass transition temperature (Tg) of 25_C during tensile loading-unloading. The process of energy storage and dissipation in the PU-SMP was investigated based on the stress-strain curves recorded by a quasi-static testing machine and the temperature changes, accompanying the deformation process, obtained by using a fast and sensitive infrared camera. The results showed that the thermomechanical behavior of the examined PU-SMP depends significantly on the strain rate. At a higher strain rate, there are higher stress and related temperature changes, which lead to greater energy dissipation. However, the energy storage values estimated during the deformation process turned out to be not significant, indicating that the work supplied to the PU-SMP structure during loading is mainly converted into heat. It should also be noted that the structural investigation revealed no crystalline phase in the investigated PU-SMP.

6

Experimental study on the dynamic tensile mechanical properties of marble under water and oil conditions

Li Chaoxin, Liu Dongyan, Zhu Yunhui

Archives of Civil Engineering

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2023

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Vol. 69, nr 3

317--330

EN

To investigate the dynamic tensile properties and energy dissipation characteristics of marble in three different conditions: dry, water-saturated, and oil-saturated, a Brazilian disk splitting test was conducted using a 50 mm diameter Hopkinson pressure bar (SHPB) device. The findings indicate that the peak strain and dynamic tensile strength of the three conditions increase with strain rate, exhibiting a clear strain rate effect. Additionally, lubricating effects of water and oil weaken internal shear sliding friction, thus promoting crack expansion. Furthermore, immersion of fluid in marble weakens the cementation of internal mineral particles, leading to lower tensile strength of marble saturated with water and oil compared to dry marble under dynamic impact. When analyzing the energy dissipation of marble, both the absorption energy and dissipation energy density increase with oil strain rate, indicating a positive correlation. Moreover, numerical results obtained from ANSYS/LS-DYNA correspond well with experimental data, thus verifying and interpreting the experimental outcomes.

7

Analysis of the seismic performances of structures reinforced by self-centering buckling-restrained braces

Jin Yongxu, Xu Man, Jia Jie

Archives of Civil Engineering

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2023

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Vol. 69, nr 3

645--663

EN

The self-centering buckling-restrained brace (SC-BRB) may achieve self-restoration for structures and, to a certain degree, diminish the substantial seismic residual deformation following rare earthquakes when compared to the usage of the conventional buckling-restrained brace (BRB). It may be possible to reduce the abrupt change in stiffness at the location of the strengthened stories and make the outrigger better at dissipating energy by improving the design of the energy-dissipation outrigger. This study compares the seismic performances of two types of energy-dissipation outriggers with BRB and SC-BRB web member designs during rare earthquakes so that the changes can be measured. The results show that using the SC-BRB web member design reduces the maximum inter-story drift ratio by an average of 7.68% and increases the average plastic-energy dissipation of the outrigger truss by 8.75%. The evaluation results show that the SC-BRB outrigger truss structure has better structural regularity and energy-dissipation performance. It has the ability to efficiently regulate the structural seismic response and lessen primary-structure damage.

8

Shear failure and mechanical behaviors of granite with discontinuous joints under dynamic disturbance: laboratory tests and numerical simulation

Gong Hangli, Wang Gang, Luo Yi, Liu Tingting, Li Xinping, Liu Xiqi

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e171, 2023

EN

To investigate the fracture mechanical behavior and failure mechanism of jointed rock mass under compression and shear load. Conventional shear tests and shear tests under normal disturbances were conducted using an electro-hydraulic servo-motor loading system. Meanwhile, the discrete-element program particle flow code was adopted to establish a numerical shear model, and to discuss the microscopic deterioration characteristics and energy dissipation mechanism during shear fracture of rocks with discontinuous joints under joint action of normal static loads and dynamic disturbance. Compared with the conventional shear tests, shear test results under normal disturbances show the following specificities in terms of their macroscopic and microscopic mechanical properties as well as energy evolution: (1) frequent dynamic disturbances accelerate the non-steady fracture process of jointed rock samples and promote occurrence of the weakening effect of shear fracture. (2) The step-like abrupt increase in micro-cracks becomes more obvious before reaching the peak shear stress. (3) The energy-storage capacity and failure resistance of the rocks are weakened. The research results are of great significance for further understanding the dynamic catastrophe effect of deep rock mass.

9

Effects of shear panel dampers on seismic response mitigation of high-speed railway simply supported bridge-track system under far-field and near-field ground motions

Jiang Liqiang, Yu Kai, Jiang Lizhong, Wen Tianxing, Hu Yi, Pang Lin

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no. e93, 2023

EN

High-speed railway lines always have to cross the seismic zone with great earthquake risks leading to serious consequences. A replaceable steel panel damper (SPD) is proposed as an energy-dissipation device to mitigate the structural seismic responses. It is simulated as a simplified nonlinear spring embedded in structural system with the force-displacement behavior derived by plate-beam theory. To investigate the effect of SPD, a typical 5-span high-speed railway simply supported bridge-track system (HSRSBTS) validated by a shaking table test is established by ANSYS. A novel damage measure, the system relative damage ratio (γSRD), is proposed to quantify the effect of SPD in the system and consider the potential component-level damage modes of both bending and shear. The structural system is investigated undergoing two ground motions suites in DBE- and MCE-level intensity, including both far-field and near-field records in transverse direction. The result indicates that a significant reduce (roughly 50%) of seismic response in rail and girder are contributed by SPD, while the system damage decreases about 10-15%, especially for near-field pulse-like ground motions with high intensity. The energy-dissipation capacity of SPDs with various configurations is examined to optimize the properties of SPD. It generally decreases with the increase in the elastic stiffness ratio r of the SPD to the fixed support, and the r = 2-2.5 are recommended in engineering practice. SPD is an effective and efficient device of structure to be adopted as an energy-dissipation component and the first defense line under far-field and near-field ground motions.

10

Cyclic response and shear mechanisms of RC short walls strengthened with engineered cementitious composites thin layers

Zhang Yangxi, Zhang Shijun, Li Tong, Deng Mingke

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e148, 2023

EN

This paper investigates the effectiveness of engineering cementitious composites (ECC) thin layers for seismic strengthening of reinforced concrete (RC) short walls with high axial load ratios. Three RC short walls with an aspect ratio of 1.1 were tested under cyclic loading: one control wall and two ECC strengthened walls, adopting two different strengthening layer schemes. The results showed that the failure mode, damage tolerance, lateral stiffness, shear strength, and energy dissipation of the strengthened walls were improved to certain extents. The mesh grid ECC layer was proved an effective and applicable technique, the shear strength and energy dissipation of the corresponding strengthened wall were improved by 37.2% and 33.5%, respectively, and the addition of mesh grid and tie bars in the ECC layer prevented the debonding failure at the ECC/concrete interface. Besides, the shear resistance mechanisms of the test specimens were idealized by the strut-and-tie model, the contribution of cracked ECC tensile strength to shear was considered in the horizontal and vertical mechanisms. The predicted shear strengths of the RC walls agreed well with the test values.

11

Study of discharge and jump of water flow from water regulatory structures in channels

Kassymbekov Zhuzbay, Shinibaev Abai, Kassymbekov Galimzhan

Journal of Water and Land Development

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2022

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no. 53

22--29

EN

One of the main causes of damage to weirs regulating the flow of water in canals is local erosion of the bottom and banks. This is mainly due to the excessive kinetic energy of the stream flow and the uneven volumetric distribution of the water flow rate at the end of the strengthening. Due to this, 35-40% of hydraulic structures fail prematurely. The aim of the research was to determine the parameters of the spatial hydraulic jump arising behind the hydrotechnical structure and the rapid expansion of the cross-section. The research showed that the hydraulic jump with a curved cylinder in the plan is a spatial form and not only dissipates the energy of the stream, but also acts as a diffuser. With the stream expansion angle values in the range of 7-10°, a highly turbulent flow remains, which still Has high kinetic energy at a distance from the end of the structure. At an angle of 25-27°, the flow is smooth, the velocity distribution is uniform across the width of the channel. In some cases, the forced expansion of the cross-section at the outflow of the weir favours the energy dissipation and uniform flow velocity distribution.

12

An experiment of energy dissipation on USBR IV stilling basin - Alternative in modification

Bantacut Alfiansyah Yulianur, Azmeri Azmeri, Jemi Faris Zahran, Ziana Ziana, Muslem Muslem

Journal of Water and Land Development

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2022

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no. 53

68--72

EN

Previous researchers have been widely studied the equation for calculating the energy dissipation in USBR Type IV, applied in the stilling basin structure as an energy dissipator. However, inefficient energy dissipating basins are commonly found in the field due to the large discharge and high water head, potentially damaging the bottom of the energy dissipating basin and its downstream river. Therefore, an energy dissipator plan fulfilling the safe specifications for the flow behaviour that occurred is required. This study aimed to determine the variation of the energy dissipators and evaluate their effect on the hydraulic jump and energy dissipation. For this purpose, a physical model was undertaken on the USBR Type IV spillway system. The novelty of this experiment showed that combination and modification dissipation features, such as floor elevation, end threshold and riprap lengthening, could effectively dissipate the impact of energy downstream. The final series exhibited a significantly higher Lj/y1 ratio, a favourable condition due to the compaction of the hydraulic jump. There was also a significant increase in the downstream tailwater depth (y2) during the jump formation. Therefore, the final series energy dissipator was better in the stilling basin design for hydraulic jump stability and compaction. The increase in energy dissipation for the final series type was the highest (98.4%) in Q2 and the lowest (84.8%) in Q10 compared to the original series. Therefore, this type can better reduce the cavitation risk damaging to the structure and downstream of the river.

13

Model considering residual stiffness and stiffness discontinuity of bolted joints

Wang Sheng-Ao, Zhu Min, Xu Zi-Jian, Guo Ming, Li Biao, Wu Fei

Journal of Theoretical and Applied Mechanics

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2022

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Vol. 60 nr 1

63--75

EN

The nonlinear dynamic behavior has an important impact on energy dissipation and vibra- tion damping characteristics of bolted joints. Firstly, the development of tangential dynamic models is summarized and analyzed. Secondly, a five-parameter Iwan model based on a trun- cated power-law distribution is proposed. The backbone and hysteresis curves are obtained. Thirdly, normalized and dimensionless analysis is performed. On the basis of the above, a more concise four-parameter Iwan model with stiffness continuity is proposed. Finally, the validity of the model is verified by comparing the energy dissipation vs excitation force amplitude curve with the experimental data.

14

A comprehensive study on the application of firefly algorithm in prediction of energy dissipation on block ramps

Mahdavi-Meymand Amin, Sulisz Wojciech, Zounemat-Kermani Mohammad

Eksploatacja i Niezawodność

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2022

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Vol. 24, no. 2

200--210

EN

In this study novel integrative machine learning models embedded with the firefly algorithm (FA) were developed and employed to predict energy dissipation on block ramps. The used models include multi-layer perceptron neural network (MLPNN), adaptive neuro-fuzzy inference system (ANFIS), group method of data handling (GMDH), support vector regression (SVR), linear equation (LE), and nonlinear regression equation (NE). The investigation focused on the evaluation of the performance of standard and integrative models in different runs. The performances of machine learning models and the nonlinear equation are higher than the linear equation. The results also show that FA increases the performance of all applied models. Moreover, the results indicate that the ANFIS-FA is the most stable integrative model in comparison to the other embedded methods and reveal that GMDH and SVR are the most stable technique among all applied models. The results also show that the accuracy of the LE-FA technique is relatively low, RMSE=0.091. The most accurate results provide SVR-FA, RMSE=0.034.

15

Minimizing movements for dissipative systems that are not gradient flows

Mimura Yoshifumi

Bulletin of the Polish Academy of Sciences. Mathematics

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2022

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Vol. 70, no. 2

133--149

EN

The time discretization method, which is a method of constructing time global solutions for gradient flows, is applied to dissipative systems in Hilbert spaces, which are not necessarily gradient flows. Equations with perturbation terms added to gradient flows are considered, and when the perturbation term is smaller than the principal term in an analytical sense, the dissipative structure of the energy is maintained, and the existence of time global solutions is shown by the time discretization method.

16

Porównanie strat mocy i sprawności silników w różnych wariantach rozwiązania

Bernatt Jakub, Gawron Stanisław, Glinka Tadeusz

Napędy i Sterowanie

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2021

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R. 23, nr 5

52--55

PL

Układy napędowe maszyn wyciągowych na szybach wydobywczych w kopalniach węgla kamiennego i rud miedzi bazują na silnikach prądu stałego wzbudzanych elektromagnetycznie. Sprawność energetyczna tych silników wynosi około 90%. W artykule przedstawiono silniki alternatywne: silnik prądu stałego wzbudzany magnesami trwałymi; silnik wzbudzany magnesami trwałymi i komutacją elektroniczną. Sprawność wymienionych silników jest większa, a ilość traconej energii w silnikach jest mniejsza.

EN

The drive systems of winding machines, on production shafts of coal mines and copper ores mines, are based on electromagnetically excited DC motors. The energy efficiency of these motors is around 90%. The alternative motors are presented in the article: DC motor excited by permanent magnets; a motor excited by permanent magnets and electronic commutation. The efficiency of these motors are greater, and the amount of energy lose in motors are smaller.

17

Cyclic behavior of precast concrete beam-column connection using steel fiber reinforced cast-in-place concrete

Noorhidana Vera Agustriana, Forth John P.

Materials Science Poland

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2021

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Vol. 39, No. 2

240--251

EN

Three equivalent exterior precast concrete beam-column (PCBC) connections have been investigated in this study in orderto analyze the effect of steel fiber reinforced concrete (SFRC) as cast-in-place (CIP) on the seismic performance of the PCBC connection. The connection was designed as a ductile connection for a moment-resisting frame and consists of a precast U-beam, precast column with corbel, interlocking bars, and CIP-concrete to connect the precast beam to precast column. The volume fractions of steel fiber incorporated within the CIP-concrete were 0%, 0.5% and 1%. A quasi-static load was applied vertically to the beam tip of the PCBC specimen. The results showed that the steel fibers contained within the CIP-concrete provided 2% increase of the maximum load, 17.7% increase of the energy dissipation, and increase in the joint stiffness of the PCBC connection. The steel fibers delayed the onset of cracking and slowed down the crack propagation, resulting in shorter cracks in the joint core of PCBC specimen, which correlates well with the deflection-hardening characteristic found from the modulus of rupture test.

18

Hydraulic jump and energy dissipation with stepped weir

Azmeri Azmeri, Basri Hairul, Yulianur Alfiansyah, Ziana Ziana, Jemi Faris Zahran, Rahmah Ridha Aulia

Journal of Water and Land Development

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2021

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no. 51

56--61

EN

Energy dissipator functions to dissipate the river-flow energy to avoid longitudinal damage to the downstream river morphology. An optimal energy dissipator planning is essential to fulfilling safe specifications regarding flow behavior. This study aims to determine the variation of energy dissipators and evaluate its effect on the hydraulic jump and energy dissipation. For this purpose, a physical model was carried out on the existing weir condition (two steps). It was also carried out on four stepped-weir variations, i.e., three-step, three-step with additional baffle blocks at the end sills, four-step, and six-step. Dimensional analysis was employed to correlate the different parameters that affect the studied phenomenon. The study shows a three-step jump shows a significantly higher Lj/y1 ratio, which is an advantage to hydraulic jumps’ compaction. The comparison of energy dissipation in all weir variations shows that the three-stepped weir has wasted more energy than other types. The energy dissipation increase of the three-step type is 20.41% higher than the existing type’s energy dissipation and much higher than other types. The dimensions of the energy dissipation basin are the ratio of the width and height of the stairs (l/h) of the three-step type (2.50). Therefore, this type is more optimal to reduce the cavitation risk, which damages the river structure and downstream area.

19

Pseudo-static test of steel-glulam composite beam-to-column exterior joints

Duan Shaowei, Liu Xinglong, Yuan Jian, Wang Zhifeng

Archives of Civil Engineering

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2021

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Vol. 67, nr 1

147--161

EN

Steel-glulam structure is a new type of composite structure,glulam have lateral support effect on steel plate, that can prevent premature buckling of steel plate and improve the stability of steel structure. In order to study the influence of column’s cross-section form on the seismic performance of steel-glulam composite beam-to-column exterior joint, the column’s cross-section form was taken as the basic variable (glulam rectangular section , H-beam section and H-beam-glulam rectangular section were used respectively). The pseudo-static tests of three composite beam-to-column joints were carried out to observe the different failure modes, and obtain the mechanical performance indexes. The experiment results demonstrated that: The energy dissipation capacity of beam-to-column exterior joint composed of glulam column was the worst, the ultimate bearing capacity and stiffness were the lowest. The ultimate bearing capacity of the exterior joints formed by the H-beam column and the H-beam-glulam composite column were both high, and their ductility coefficients were similar, while the former had better energy dissipation capacity.

20

Study on friction behavior at the interface between prosthetic socket and liner

Xie Jingyang, Liu Xidong, Tang Jianhua, Li Xi, Li Wei

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 1

83--93

EN

Purpose: The friction characteristics at the interface between prosthetic socket and liner have an important influence on the walking function and wearing comfort of amputees. The frictional behavior at the prosthetic socket/liner interface can provide theoretical guidance for the design and selection of prosthetic materials. So it is of great significance to study the friction behavior at prosthetic socket/liner interface. Methods: The surface roughnesses of the prosthetic socket and liner materials were measured by a laser confocal microscope. The frictional behavior at the prosthetic socket/liner interface was studied on a UMT TriboLab Tribometer by simulating the reciprocating sliding contact mode. An infrared camera was used to take thermal images and then calculated the temperature increase at the socket/liner interface. Results: The coefficient of friction of the silicon rubber fabric are significantly smaller than that of the foam liner materials. The frictional energy dissipation at the liner/acrylic socket interface is the smallest, while it is greater for 3D-printed socket materials. Meanwhile, the temperature increase has a positive correlation to the coefficient of friction and frictional energy dissipation. Conclusions: The three kinds of 3D-printed materials with high surface roughness have higher interface coefficient of friction and energy dissipation than acrylic material. The stiffness and energy consumption play an important role in the interface friction characteristics of the prosthetic liner materials. The appropriate coefficient of friction at the surface between prosthetic socket and liner is essential. A type of the reinforcement fiber has influence on the friction behavior of the 3D-printed reinforced nylon.