impact behavior
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2022 ◽  
Vol 171 ◽  
pp. 108722
Author(s):  
Wei Gao ◽  
Xiaoqiang He ◽  
Jiawen Wang ◽  
Y.T. Feng ◽  
Chengyong Wang

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 441
Author(s):  
Teghreed H. Ibrahim ◽  
Abbas A. Allawi ◽  
Ayman El-Zohairy

The present study experimentally and numerically investigated the impact behavior of composite reinforced concrete (RC) beams with the pultruded I-GFRP and I-steel beams. Eight specimens of two groups were cast in different configurations. The first group consisted of four specimens and was tested under static load to provide reference results for the second group. The four specimens in the second group were tested first under impact loading and then static loading to determine the residual static strengths of the impacted specimens. The test variables considered the type of encased I-section (steel and GFRP), presence of shear connectors, and drop height during impact tests. A mass of 42.5 kg was dropped on the top surface at the mid-span of the tested beams from five different heights: 250, 500, 1000, 1500, and 1900 mm. Moreover, nonlinear Finite Element (FE) models were developed and validated using the experimental data. Static loading was defined as a displacement-controlled loading and the impact loading was modeled as dynamic explicit analysis with different drop velocities. The validated models were used to conduct a parametric study to investigate the effect of the concrete compressive strength on the performance of the composite beams under static and impact loadings. For the composite specimen with steel I-sction, the maximum impact force was 190% greater than the reference specimen NR-I at a drop height of 1900 mm, whereas the maximum impact forces for the specimens composite specimens with GFRP I-sction without and with shear connectors were 19% and 77%, respectively, more significant than the reference beam at the same drop height. The high stiffness for the steel I-beams relative to the GFRP I-beam was the reason for this difference in behavior. The concrete compressive strength was more effective in improving the impact behavior of the composite specimens relative to those without GFRP I-beams.


2022 ◽  
Vol 905 ◽  
pp. 3-8
Author(s):  
Eser Yarar ◽  
Alpay Tamer Erturk

Surface mechanical attrition treatment enhances the mechanical properties of metallic materials by inducing high strength layer on the top surface. In this study, multiple-shot impact behavior was modeled for the 7075-T6 aluminum alloy to achieve maximum magnitudes of equivalent stress, plastic strain, residual stress depth, and residual stress. Finite element simulations have been carried out to investigate the effect of selected framework on stress and strains in constituent. The plastic deformation process during SMAT was analyzed using ANSYS/AUTODYN explicit dynamic solver according to shot velocity and diameter with a dynamic explicit finite element method (FEM). Deformation behavior was evaluated after multiple-shot impact.


Structures ◽  
2022 ◽  
Vol 35 ◽  
pp. 818-832
Author(s):  
Tolga Yılmaz ◽  
Özgür Anil ◽  
R. Tuğrul Erdem

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 301
Author(s):  
Kamila Sałasińska ◽  
Peteris Cabulis ◽  
Mikelis Kirpluks ◽  
Andrejs Kovalovs ◽  
Paweł Kozikowski ◽  
...  

The production of hybrid layered composites allows comprehensive modification of their properties and adaptation to the final expectations. Different methods, such as hand lay-up, vacuum bagging, and resin infusion were applied to manufacture the hybrid composites. In turn, fabrics used for manufacturing composites were made of glass (G), aramid (A), carbon (C), basalt (B), and flax (F) fibers. Flexural, puncture impact behavior, and cone calorimetry tests were applied to establish the effect of the manufacturing method and the fabrics layout on the mechanical and fire behavior of epoxy-based laminates. The lowest flammability and smoke emission were noted for composites made by vacuum bagging (approximately 40% lower values of total smoke release compared with composites made by the hand lay-up method). It was demonstrated that multi-layer hybrid composites made by vacuum bagging might enhance the fire safety levels and simultaneously maintain high mechanical properties designed for, e.g., the railway and automotive industries.


2021 ◽  
Vol 4 (4) ◽  
pp. 239-248
Author(s):  
Mehmet Fatih Şahan ◽  
Fatih Ali Öncel ◽  
İsmail Ünsal

This study investigated the effect of fiber ratio on the impact behavior of polypropylene fiber reinforced concrete cube and beam samples. Plain concrete mixtures for control samples and polypropylene fiber-reinforced concrete mixtures with fiber ratios of %0.22, %0.44, and %0.66 by volume were prepared. An instrumented drop-weight impact system was used for the dynamic tests. Static compression tests, three-point bending tests, and impact tests were performed on beam samples (with the dimension of 100×100×500 mm). Static compression and impact tests were performed on cube samples (with the size of 100 mm). It was observed that the fracture properties of polypropylene fiber reinforced concrete for both cube and beam samples were better than the control samples under impact. The crack width in the beams under the impact decreased with the increase in polypropylene fiber ratio. The cube and beam concrete samples reinforced with polypropylene fibers absorbed the impact energy better than the control samples.


2021 ◽  
Vol 21 (6) ◽  
pp. 9-19
Author(s):  
Kyoungju Kim ◽  
Hyunung Bae ◽  
Jongmin Kim

Transition is a type of barrier that connects other barriers with different grades and shapes. Even if each barrier satisfies the performance, it may not be satisfied in transition. Therefore, collision safety requires a special design and examination. In this study, we investigated national and foreign standards and situations for the proper configuration of the transition and analyzed the impact behavior of the general transition using impact simulations. We developed a transition system that could ensure the stable performance of various grades by analyzing the behavior and confirmed based on the full-scale crash test (SB2 level).


2021 ◽  
Vol 12 ◽  
Author(s):  
Li Zhang ◽  
Yongtao Zhou

The third-generation incubator is generally characterized by embedment of social networking and customized incubation services are closely embedded in the social networking. How the social networking play their role in the process that customized incubation services facilitate the growth of tenant? In order to disclose whether social networking services (SNS) mediate the impact of customized incubation services on the growth of tenants, this article focuses on the whole process where customized services facilitate the growth of tenants by means of social networking services. First, it employs situational theory and contingency theory to analysis why customized services result in behavior of social networking services; second, it explores why behavior of social networking services facilitates the growth of tenants based on co-production theory and social network theory; next, it conduct a study on the direct relationship between customized services and growth of tenants anchoring on the theory of co-production, customer satisfaction, and dynamic environment. Based on these theories, it develops the overall theoretical model of mediating effect. Following that, it conducts empirical test: it has first ascertained whether there is a positive relationship between customized services and growth of tenants. Then, three paths of the theoretical model have been measured by means of the structural model. At the same time, the t-test and the Sobel test are employed to justify their significance. If we only contemplate customized incubation services and growth of tenants, they are positively correlative. On the other hand, if referring to the role of social networking services in this process, we disclosed that not only customized incubation services positively impact behavior of social networking services, but also behavior of social networking services positively facilitates the growth of tenants; at the same time, the customized incubation services exhibit no direct impact on the growth of tenants otherwise. It witnesses that the behavior of social networking services fully mediates the relationship between customized services and the growth of tenants. As a result, we should promote incubation services to be deeply embedded in social networking services; incubator management should even improve the capability to deal with big data embedded in social networking services. In additional, entrepreneurial ecosystems should be also embedded in social networks intensively.


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