scholarly journals Experimental Study on Mechanical Properties of a Medium Size Box-Type Corrugated Steel Bridge

2021 ◽  
Author(s):  
Wenqiang Fu ◽  
Xinsha Fu ◽  
Yuting He ◽  
Baijian Li
Keyword(s):  
Mechanical Properties ◽  
Dynamic Load ◽  
Static Load ◽  
Design Method ◽  
Axial Stress ◽  
Structure Design ◽  
Steel Bridge ◽  
Maximum Value ◽  
Box Structure ◽  
Load Conditions

Different from an arch bridge, the load-carrying capacity of a box structure mainly depends on the bending capacity of corrugated steel. This paper explores the mechanical properties of a corrugated steel box bridge. The mechanical properties of a 13 m span corrugated steel box bridge under static and dynamic loads were tested. Three static load conditions were tested, and four dynamic load conditions were tested, including 20 km/h, 40 km/h, 60 km/h, and 80 km/h. Through the analysis of section strain, vault displacement, dynamic strain, and internal force, the following conclusions can be drawn: (1) when the static load changes from the right arch foot and vault to the left arch foot, the strain value of each measuring point continues to increase, which may be caused by the accumulation of deformation due to the adjustment of the stress state of the soil and corrugated steel caused by loading; (2) the displacement change in the test is more sensitive than the strain change; (3) the vault strain reaches the maximum value at a specific speed of 60 km/h. This is related to the structural resonance caused by vehicle operation, and the natural frequency of the corrugated steel box bridge can be determined by a field vehicle dynamic load test; (4) the damping value of an embedded corrugated steel bridge is large, and the energy dissipation capacity is strong, which is very beneficial to structural earthquake resistance and to reducing the structural resonance under traffic load; (5) the dynamic increasing strain coefficient is less than 1, which means that the strain caused by a dynamic load is far less than that caused by a static load, and it reaches the maximum value at a certain speed (60km/h); (6) the maximum bending stress and maximum axial stress of the corrugated steel box bridge tested in this paper are basically the same, which indicates that the axial stress of the box structure cannot be ignored. However, the box structure design method proposed in the CHBDC code does not consider the axial stress, so it is necessary to further improve the box structure design method; (7) most of the axial force of a box corrugated steel bridge is tensile force. The pavement structure layer has an effect on the overall performance of the corrugated steel box bridge, which is similar to the decompression plate: it makes the overall stress (I ∼ V section) more uniform and the bending moment smaller.

Experimental study on mechanical behavior of combined joint using adhesives and high strength bolts

2021 ◽  
Author(s):  
Takuya Kamino ◽  
Takashi Fujimoto ◽  
Takashi Yamaguchi ◽  
Yasumoto Aoki ◽  
Shinsuke Akamatsu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Design Method ◽  
High Strength ◽  
Corrosion Damage ◽  
Epoxy Adhesive ◽  
Steel Bridge ◽  
Slip Coefficient ◽  
Constraint Effect ◽  
Slip Resistance

<p>As a repair for corrosion damage of a steel bridge, a patch plate-repair using high strength bolts is generally applied. This method requires the surface of the damaged corroded part filled with an epoxy adhesive flat. The load transferring mechanism and slip resistance of such a combined joint with adhesives and high strength frictional bolts aren't clear. Since the shear strength of an adhesive might be increased due to constraint by the bolt axial force, the combined joint's slip resistance would be increased. To clarify the mechanical properties of the combined joint and to propose a new design method for such joints, two experiments have been conducted. The first was a frictional force experiment for adhesive specimens subjected to contact pressure on the surface to evaluate the constraint effect of adhesive on shear strength quantitatively. The last one is a slippage experiment for the combined joints to evaluate its slip coefficient.</p>

Structure Design and Mechanics Calculation of Aqueduct Model

2014 ◽  
Vol 488-489 ◽  
pp. 381-384
Author(s):  
Xue Chen Li ◽  
Peng Chen ◽  
Yong Ye ◽  
Cheng Hao Wang
Keyword(s):  
Mechanical Properties ◽  
Irrigation Water ◽  
Static Load ◽  
Water System ◽  
Structure Design ◽  
Structure Calculation ◽  
Continuous Beam ◽  
Water Delivery ◽  
Practical Application ◽  
Whole Process

Aqueduct is a conveyance structure which can across the channel, depressions, roads and railways and its conveyance water system is mainly composed of bridges, tunnels or ditch. Aqueduct is widely used in hydraulic engineering, and plays a role in irrigation ,water delivery , drainage and desilting. A large aqueduct can also be used for navigation. In the paper, based on the aqueduct design, aqueduct model making, aqueduct structure calculation and static load experiment, the whole process of design and calculation of continuous beam truss aqueduct model are performed, and the analysis of its mechanical properties are also carried on. These results are useful for the practical application of aqueduct structure.

scholarly journals Experimental Study on Mechanical Properties and Energy Dissipation of Gas Coal under Dynamic and Static Loads

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Xiang Cheng ◽  
Guangming Zhao ◽  
Yingming Li ◽  
Xiangrui Meng ◽  
Qingyi Tu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Dissipation ◽  
Strain Rate ◽  
Dynamic Load ◽  
Coal Sample ◽  
Static Load ◽  
Dissipated Energy ◽  
Dissipation Energy ◽  
Static Loads ◽  
Gas Coal

In order to study the mechanical properties and energy dissipation of gas coal under dynamic and static loads, the static loading and impact tests of different strain rates were carried out by the testing systems of SZW-1000 microcomputer servo pressure tester and separated Hopkinson pressure bar (SHPB) for gas coal in the Panxie Coal Field in Huainan City. In the test, the influence laws of various loading patterns on mechanical properties, failure characteristics, and energy dissipation of gas coal sample were analyzed. The results showed that the stress-strain curve of coal gas under dynamic load had no micropore compaction stage compared with that under static load. Dynamic compressive strength, dynamic strength growth factor, mixed dynamic elasticity modulus, and dissipation energy were all highly correlated with strain rate, whereas energy dissipation rate was uncorrelated with strain rate. In addition, the gas coal sample with lower strain had small dissipated energy, and it developed a splitting failure mode. With the increase of strain rate, the dissipation energy increased and the crushing degree of gas coal intensified, finally presenting a compressive failure mode. Based on the comparison of dissipated energy densities of different gas coal samples, given the same dissipated energy density, the failure degree of sample under dynamic load was higher than that under static load.

Dynamic Loading of Synchronous Belts

2000 ◽  
Vol 124 (1) ◽  
pp. 79-85 ◽  
Author(s):  
Tomas Johannesson ◽  
Martin Distner
Keyword(s):  
Experimental Data ◽  
Dynamic Loading ◽  
Dynamic Load ◽  
Coulomb Friction ◽  
Static Load ◽  
Belt Drives ◽  
History Effects ◽  
Timing Belt ◽  
Load Conditions ◽  
Good Agreement

In automotive timing belt drives friction history effects must be taken into concern due to rapidly changing loads. Here a spring based model capable of handling dynamic load conditions is presented. The model also covers partial meshing effects and utilizes Coulomb friction. The model shows good agreement with experimental data found in literature. It is proven that when simulating synchronous belt drives during rapidly changing load conditions, using models for quasi-static load conditions stepwise are not sufficient.

Validating the New Equivalent Static Design Method of Spacecraft Structures in Random Vibration by Test

2013 ◽  
Vol 419 ◽  
pp. 464-469
Author(s):  
Yu Mei Zhang ◽  
Zeng Yao Han ◽  
Si Dian Shi ◽  
Li Meng Tan
Keyword(s):  
Yield Strength ◽  
Time Domain ◽  
Random Vibration ◽  
Static Load ◽  
Design Method ◽  
Structure Design ◽  
Equivalent Static Load ◽  
Static Yield ◽  
Dynamic Yield Strength ◽  
Dynamic Yield

Random vibration is one of dynamic environments of spacecraft during launch. In engineering, design load was usually equivalent static load based on acceleration. A new equivalent static load based on strain or stress was presented by the writer. To validate the new equivalent static design method, random vibration test was designed including test article and test specification, and signal processing was in time domain; static test was designed to compare static yield strength and dynamic yield strength, and dynamic yield strength was 50% -80% higher than static yield strength; measured data in time domain was analyzed , and the equivalent static design of strain based on first passage model can be used to spacecraft structure design. And it will decrease the mass of spacecraft structure obviously.

scholarly journals ALTERNATIF UJI BEBAN PADA STRUKTUR (STUDI KASUS : JEMBATAN BAJA)

2021 ◽  
Vol 5 (1) ◽  
pp. 27
Author(s):  
Chairul Soleh ◽  
Josia Irwan Rastandi
Keyword(s):  
Natural Frequency ◽  
Dynamic Load ◽  
Static Load ◽  
Natural Frequencies ◽  
Load Test ◽  
Vibration Test ◽  
Steel Bridge ◽  
Bridge Structure ◽  
Static Load Test ◽  
Dynamic Load Test

The most common structural load test that has been widely used is the static load test. An alternative to the structural load test is dynamic load test. Dynamic testing is a test carried out to determine level of structural stiffness or structural elements stiffness in the form of natural frequencies, while the static load test is intended to obtain responses of static loading from the structure in the form of deflection. The discussion will emphasize the correlation between static load test and dynamic load test. To correlate the static load test with the vibration test, a reference or value that comes from modeling or theoretical analysis is needed. Structural modeling is carried out to obtain the theoretical natural frequency and the theoretical deflection which will then be compared with the natural frequency of the vibration test (dynamic). If the frequency of the test results and the theoretical frequency are compared to the theoretical deflection, the prediction of the test deflection will be obtained. The correlation between the predicted deflection of the test and deflection of the static load test is quite close with a difference of less than 12%. Judging from the above correlation, periodic inspections of the tested structures can be considered for vibration testing only. The types of structures reviewed are simple span steel bridge structure, simple span + link slab steel bridge structure and continuous span steel bridge structure. Keywords: modeling; natural frequencies; vibration testing; static load test  AbstrakUji beban struktur yang umum dan sudah banyak dilakukan adalah uji beban statik. Alternatif lain dari uji beban adalah dengan melakukan pengujian vibrasi (dinamik) pada struktur. Pengujian vibrasi (dinamik) dilakukan untuk mengetahui tingkat kekakuan struktur atau elemen struktur berupa frekuensi alami, sedangkan uji beban statik dimaksudkan untuk mendapatkan respons hasil pembebanan statik dari struktur berupa lendutan. Pembahasan akan menekankan kepada korelasi antara uji beban statik dan uji beban vibrasi (dinamik). Untuk mengkorelasikan pengujian beban statik terhadap pengujian vibrasi (dinamik) diperlukan suatu acuan atau nilai yang berasal dari analisa pemodelan atau teoritis. Pemodelan struktur dilakukan untuk mendapatkan frekuensi alami secara teoritis dan lendutan teoritis yang kemudian akan dibandingkan dengan frekuensi alami hasil uji vibrasi (dinamik).  Jika frekuensi hasil uji dan frekuensi teoritis dibandingkan terhadap lendutan teoritis maka akan didapatkan prediksi lendutan uji. Hasil korelasi antara prediksi lendutan uji terhadap lendutan uji beban statik cukup mendekati dengan perbedaan kurang dari 12%. Dilihat dari korelasi diatas, maka untuk pemeriksaan berkala pada struktur yang telah diuji dapat dipertimbangkan untuk dilakukan pengujian vibrasi saja. Jenis struktur yang ditinjau adalah struktur jembatan baja simple span, simple span + link slab dan continuous span.

scholarly journals Multi-Branch Cable Harness Layout Design Based on Genetic Algorithm with Probabilistic Roadmap Method

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Yingfeng Zhao ◽  
Jianhua Liu ◽  
Jiangtao Ma ◽  
Linlin Wu
Keyword(s):  
Genetic Algorithm ◽  
Topological Structure ◽  
Design Method ◽  
Route Planning ◽  
Layout Design ◽  
Structure Design ◽  
Prototype System ◽  
Cable Harness ◽  
Probabilistic Roadmap ◽  
Probabilistic Roadmap Method

AbstractCurrent studies on cable harness layouts have mainly focused on cable harness route planning. However, the topological structure of a cable harness is also extremely complex, and the branch structure of the cable harness can affect the route of the cable harness layout. The topological structure design of the cable harness is a key to such a layout. In this paper, a novel multi-branch cable harness layout design method is presented, which unites the probabilistic roadmap method (PRM) and the genetic algorithm. First, the engineering constraints of the cable harness layout are presented. An obstacle-based PRM used to construct non-interference and near to the surface roadmap is then described. In addition, a new genetic algorithm is proposed, and the algorithm structure of which is redesigned. In addition, the operation probability formula related to fitness is proposed to promote the efficiency of the branch structure design of the cable harness. A prototype system of a cable harness layout design was developed based on the method described in this study, and the method is applied to two scenarios to verify that a quality cable harness layout can be efficiently obtained using the proposed method. In summary, the cable harness layout design method described in this study can be used to quickly design a reasonable topological structure of a cable harness and to search for the corresponding routes of such a harness.

scholarly journals Effect of Structural Differences on the Mechanical Properties of 3D Integrated Woven Spacer Sandwich Composites

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4284
Author(s):  
Lvtao Zhu ◽  
Mahfuz Bin Rahman ◽  
Zhenxing Wang
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Three Dimensional ◽  
Sheet Thickness ◽  
Physical And Mechanical Properties ◽  
Sandwich Composites ◽  
Computed Tomography Images ◽  
And Performance ◽  
Industrial Textiles ◽  
Load Conditions

Three-dimensional integrated woven spacer sandwich composites have been widely used as industrial textiles for many applications due to their superior physical and mechanical properties. In this research, 3D integrated woven spacer sandwich composites of five different specifications were produced, and the mechanical properties and performance were investigated under different load conditions. XR-CT (X-ray computed tomography) images were employed to visualize the microstructural details and analyze the fracture morphologies of fractured specimens under different load conditions. In addition, the effects of warp and weft direction, face sheet thickness, and core pile height on the mechanical properties and performance of the composite materials were analyzed. This investigation can provide significant guidance to help determine the structure of composite materials and design new products according to the required mechanical properties.

scholarly journals Fabrication of Polycaprolactone/Nano Hydroxyapatite (PCL/nHA) 3D Scaffold with Enhanced In Vitro Cell Response via Design for Additive Manufacturing (DfAM)

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1394
Author(s):  
Yong Sang Cho ◽  
So-Jung Gwak ◽  
Young-Sam Cho
Keyword(s):  
Mechanical Properties ◽  
Cell Response ◽  
Structural Characteristics ◽  
Structure Design ◽  
Compressive Modulus ◽  
Control Group ◽  
Design For Additive Manufacturing ◽  
3D Scaffold ◽  
3D Printed

In this study, we investigated the dual-pore kagome-structure design of a 3D-printed scaffold with enhanced in vitro cell response and compared the mechanical properties with 3D-printed scaffolds with conventional or offset patterns. The compressive modulus of the 3D-printed scaffold with the proposed design was found to resemble that of the 3D-printed scaffold with a conventional pattern at similar pore sizes despite higher porosity. Furthermore, the compressive modulus of the proposed scaffold surpassed that of the 3D-printed scaffold with conventional and offset patterns at similar porosities owing to the structural characteristics of the kagome structure. Regarding the in vitro cell response, cell adhesion, cell growth, and ALP concentration of the proposed scaffold for 14 days was superior to those of the control group scaffolds. Consequently, we found that the mechanical properties and in vitro cell response of the 3D-printed scaffold could be improved by kagome and dual-pore structures through DfAM. Moreover, we revealed that the dual-pore structure is effective for the in vitro cell response compared to the structures possessing conventional and offset patterns.

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