Present Status and Future Problems on the Impact Resistance Performance Design of Civil Engineering Protective Structures

2014 ◽  
Vol 566 ◽  
pp. 10-25 ◽  
Author(s):  
Yoshimi Sonoda
Keyword(s):  
Civil Engineering ◽  
Impact Resistance ◽  
Design Methods ◽  
Current Status ◽  
Research Committee ◽  
Engineering Structures ◽  
Design Concepts ◽  
Protective Structures ◽  
Resistance Performance ◽  
The Impact

There are many civil engineering structures that have different systems and required functions. Their design methods do not have consistent design concepts. Thus, it has been pointed out the necessity of universal concepts on assumed external actions and risk for various structures and on the required level of safety. In order to meet those demands, a research committee as part of Japan Society of Civil Engineers summarizing the basic concepts of impact resistance design. This paper introduces several design methods of structures subjected to impact loads, and presents the current status and remaining issues of establishing new performance-based design methods.

Study and Application of Health Monitoring by Fiber Optic Sensors in Civil Engineering

2003 ◽  
Author(s):  
Hong-Nan Li ◽  
Dong-Sheng Li ◽  
Su-Yan Wang
Keyword(s):  
Health Monitoring ◽  
Fiber Optic ◽  
Civil Engineering ◽  
Fiber Optic Sensor ◽  
Current Status ◽  
Fibre Optic ◽  
Engineering Structures ◽  
Monitoring Method ◽  
Structural Health ◽  
Potential Damage

In civil engineering, the smart health monitoring method by use of fiber optic sensor is a new approach that evaluates the structural health situation. The current status in applications of fibre optic structural health monitoring in civil engineering structures with a brief introduction of the advantages, basic principles of fibre optic sensors is described in this paper. Leakage detection and potential damage to pipelines are emphasized. Finally, existing problems for packing and implementing fibre optic sensors in structures are discussed.

Flexural and Creep Performances of Wood Fiber Reinforced Polymer Composite

2016 ◽  
Vol 850 ◽  
pp. 91-95
Author(s):  
Yan Cao ◽  
Wei Hong Wang ◽  
Hai Long Xu ◽  
Qing Wen Wang
Keyword(s):  
Wood Fiber ◽  
Impact Resistance ◽  
Fiber Reinforced Polymer ◽  
Creep Recovery ◽  
Fiber Reinforced ◽  
Impact Performance ◽  
Reinforced Polymer ◽  
Fiber Size ◽  
Resistance Performance ◽  
The Impact

In order to optimize the size of wood fiber reinforced polymer, and extend the application field of wood fiber reinforced polymer composites and improve the safety of their use, four size of wood fiber reinforced high-density polyethylene (HDPE) composites were prepared by forming mat-compression molding. The four kinds of fibers of different size include 80-120 mesh, 40-80 mesh, 20-40 mesh and 10-20 mesh fibers. The flexural performance, impact resistance performance and 24 hours creep - 24 hours recovery of the composites are studied. Fiber of 20-40 mesh presents the best flexural and impact resistance performance. The flexural strength, the elastic modulus and the impact strength reach 26.71MPa, 2.73Gpa and 6.88 KJ/m2 respectively. The impact performance of wood fiber/HDPE composites do not change a lot, while the fiber size increases from 10 to 80 mesh. However, the composites containing 80-120 mesh fibers has minimum impact performance. The creep performance of the wood fiber/HDPE composites with 80-120 mesh is the worst. After 24h creep test, the strain of the other three groups is almost the same. Creep recovery of the composites reinforced with 40-80 mesh fiber is the worst (61.74%). The creep recovery of the other three is above seven percent. Therefore, excessively large or small fiber size proves to be negative to improve the mechanical and creep performance, and polymer composites reinforced by them are not suitable for work under long-term load.

scholarly journals Assessment of the Impact Resistance of a Composite Material with EN AW-7075 Matrix Reinforced with α-Al2O3 Particles Using a 7.62 × 39 mm Projectile

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 769 ◽  
Author(s):  
Adam Kurzawa ◽  
Dariusz Pyka ◽  
Krzysztof Jamroziak ◽  
Marcin Bajkowski ◽  
Miroslaw Bocian ◽  
...  
Keyword(s):  
Composite Materials ◽  
Matrix Material ◽  
Impact Resistance ◽  
Constitutive Models ◽  
Pressure Infiltration ◽  
Destruction Mechanism ◽  
Al2o3 Particles ◽  
Α Al2o3 ◽  
Protective Structures ◽  
The Impact

The paper presents the results of studies on the effects of shooting composite materials produced by pressure infiltration with the EN AW-7075 alloy as a matrix and reinforcement in the form of preforms made of α-Al2O3 particles. Composite materials were made with two reinforcement contents (i.e., 30% and 40% vol. of α-Al2O3 particles). The composites produced in the form of 12 mm thick plates were subjected to impact loads from a 7.62 × 39 FMJ M43 projectile fired from a Kalashnikov. The samples of composites with different contents of strengthening particles were subjected to detailed microscopic examination to determine the mechanism of destruction. The effect of a projectile impact on the microstructure of the material within the perforation holes was identified. There were radial cracks found around the puncture holes and brittle fragmentation of the front surfaces of the specimens. The change in the volume of the reinforcement significantly affected the inlet, puncture and outlet diameters. The observations confirmed that brittle cracking dominated the destruction mechanism and the crack propagation front ran mainly in the matrix material and along the boundaries of the α-Al2O3 particles. In turn, numerical tests were conducted to describe the physical phenomena occurring due to the erosion of a projectile hitting a composite casing. They were performed with the use of the ABAQUS program. Based on constitutive models, the material constants developed from the identification of material properties were modelled and the finite element was generated from homogenization in the form of a representative volume element (RVE). The results of microscopic investigations of the destruction mechanism and numerical investigations were combined. The conducted tests and analyses shed light on the application possibilities of aluminium composites reinforced with Al2O3 particles in the construction of add-on-armour protective structures.

scholarly journals On ways to increase protection of special structures from impact action

2021 ◽  
pp. 52-57
Author(s):  
Andriy Andrukhiv ◽  
Andriy Baranov ◽  
Nadiia Huzyk ◽  
Bohdan Sokil ◽  
Mariia Sokil
Keyword(s):  
Mechanical Characteristics ◽  
Dynamic Effect ◽  
External Action ◽  
Engineering Structures ◽  
Discrete Function ◽  
Impact Action ◽  
Protective Element ◽  
Protective Structures ◽  
The Impact ◽  
Physical And Mechanical Characteristics

The technique of research of dynamic processes of elements of engineering constructions of special purpose from explosive action of projectiles is developed. Elastically reinforced beams with hinged ends were chosen for the physical model of elements of engineering structures. It is assumed that the elastic properties of the latter satisfy the nonlinear technical law of elasticity. A mathematical model of the process of a series of impact actions of projectiles at different points of the element of the protective structure is constructed. The latter is a boundary value problem for a partial differential equation. Its peculiarity is that the external dynamic action is a discrete function of linear and time variables. To determine the dynamic effect of a series of impacts on the object under study, and thus the level of protection of the structure, the basic ideas of perturbation theory methods are extended to new classes of systems. This allowed to obtain an analytical dependence of the deformation of the elastically reinforced element on the basic physical and mechanical characteristics of the material of the protective element, its reinforcement and the characteristics of the external action of the projectiles. It is shown that the most dangerous cases, given the security of the structure, are those when the impact is repeated at equal intervals, in addition, the point of impact is closer to the middle of the protective element. The obtained theoretical results can be the basis for selection at the stage of designing the main physical and mechanical characteristics of the elements of engineering structures and their reinforcement in order to reliably protect personnel and equipment from the maximum possible impact on it of the shock series of projectiles. The reliability of the obtained results is confirmed by: a) generalization of widely tested methods to new classes of dynamical systems; b) obtaining in the limit case the consequences known in scientific sources concerning the linearly elastic characteristics of the elements of protective structures; c) their consistency with the essence of the physical process itself, which is considered in the work.

Based on the Digital Design of the Pneumatic Pick Force Analysis and Research of Key Parts

2013 ◽  
Vol 753-755 ◽  
pp. 1347-1350
Author(s):  
Chen Shen ◽  
Hua Liang Gui ◽  
Ming Ming Wu
Keyword(s):  
Mechanical Performance ◽  
Raw Materials ◽  
Design Method ◽  
Impact Resistance ◽  
Digital Design ◽  
Working Process ◽  
Air Power ◽  
Power Machinery ◽  
Resistance Performance ◽  
The Impact

Pick is a hand-held machine of the air power machinery, using compressed air as power, hit a rundown coal and ore body or other objects. In the working process of the pneumatic pick, pick cylinder under different loading easily lead to early obsolescence. In order to improve the impact resistance performance to pick picks, prolong the service life of pneumatic pick, based on the digital design method for pneumatic pick pick cylinder is modeled, and based on the simulated stress analysis, for the process improvement, improve its mechanical performance, reduce the waste of raw materials.

Preparation and Properties of PS/PP/Nano-TiO2 Composites

2013 ◽  
Vol 750-752 ◽  
pp. 3-6
Author(s):  
Shou Wu Yu ◽  
Shu Juan Xiao ◽  
Peng Bo Zhang ◽  
Li Jie Zhang ◽  
Yu Qing Li
Keyword(s):  
Mechanical Properties ◽  
Impact Resistance ◽  
Heat Stability ◽  
Melt Index ◽  
Melt Compounding ◽  
Resistance Performance ◽  
The Impact ◽  
Addition Amount

PS/PP/nano-TiO2 composites are prepared via melt compounding method. We study on the effects of mechanical properties, rheological, heat stability and microscopic structures on the composites. Results show that the impact resistance performance, compatibility, melt index, etc are associated with the addition amount of TiO2.

scholarly journals Effect of Uniaxial Fatigue Aging and Fabric Orientation on Low Impact Velocity Response of Glass Fibers/Elium Acrylic Composite Laminates

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4089
Author(s):  
Tomasz Libura ◽  
Rodrigue Matadi Boumbimba ◽  
Alexis Rusinek ◽  
Zbigniew L. Kowalewski ◽  
Tadeusz Szymczak ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Impact Energy ◽  
Composite Structures ◽  
Glass Fibers ◽  
Impact Resistance ◽  
Woven Fabric ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Engineering Structures ◽  
The Impact

Impact resistance is one of the most critical features of composite structures, and therefore, its examination for a new material has a fundamental importance. This paper is devoted to the characterization of the fully recyclable thermoplastic ELIUM acrylic resin reinforced by glass fabric woven, which belongs to a new category of materials requiring advanced testing before their application in responsible elements of engineering structures. Its high strength, low weight as well as low production cost give excellent opportunities for its wide application in the automotive industry as a replacement of the thermoset-based laminates. The study presents an experimental work concerning the effect of damage due to low and high cyclic fatigue aging of two groups of specimens, first with the woven fabric orientations of [0°/90°]4 and secondly with [45°/45°]4, on the low impact velocity properties. The impact resistance was measured in terms of load peak, absorbed energy, penetration threshold and damage analysis. The low velocity impact results indicate that the uniaxial cyclic loading (fatigue aging) of the material leads to the reduction of impact resistance, especially at the high impact energy levels. Scanning Electron Microscopy (SEM) and Computed Tomography (CT) scan observations reveal that the damage area grows with the increase of both strain amplitude and impact energy.

Influence Study of Reinforced Fiber on the Impact Resistance Performance of Recycled Aggregate Concrete

2011 ◽  
Vol 418-420 ◽  
pp. 250-253
Author(s):  
Lin Gao ◽  
Yan Shi ◽  
Ya Chang Liu
Keyword(s):  
Impact Resistance ◽  
Polypropylene Fiber ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Hybrid Fiber ◽  
Concrete Technology ◽  
Aggregate Concrete ◽  
Reinforced Fiber ◽  
Resistance Performance ◽  
The Impact

Recycled aggregate concrete technology has been payed widely attention. In addition to the research on the basic performance of recycled aggregate concrete, the impact resistance performance of recycled aggregate concrete was also involved. Through mixing respectively steel fiber, polypropylene fiber and steel-polypropylene hybrid fiber into the recycled aggregate concrete, the writer studied the impact resistance performance of fiber-reinforced recycled aggregate concrete, and compared the influence of reinforced fiber on the impact resistance performance of recycled aggregate concrete.

scholarly journals Impact of land-cover change related to urbanization on surface runoff estimation

2018 ◽  
Vol 196 ◽  
pp. 03014 ◽  
Author(s):  
Paweł Gilewski ◽  
Arkadiusz Węglarz
Keyword(s):  
Land Cover ◽  
Land Cover Change ◽  
Surface Runoff ◽  
Civil Engineering ◽  
Hydrological Cycle ◽  
Engineering Structures ◽  
Mountainous Catchment ◽  
Impact Of Urbanization ◽  
The Impact ◽  
Impervious Areas

Civil engineering structures are highly responsible for the negative aspects of urbanization on the hydrological cycle. Due to the land cover change and an increase of impervious areas the risk of flooding can rise significantly. The paper presents the impact of urbanization processes on surface runoff estimation for a small mountainous catchment between 1990-2012.

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