scholarly journals Post Tensioned CFRP tubes for improved energy absorption

2021 ◽  
Author(s):  
Venkateswarlu Gattineni ◽  
◽  
Venukumar Nathi ◽  
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Absorption Capacity ◽  
Energy Absorption Capacity ◽  
Element Analysis ◽  
Simulation Techniques ◽  
Thin Tube ◽  
Post Tensioning ◽  
Cfrp Tubes ◽  
Post Tensioned

Thin-walled tubes made of CFRP (Carbon fiber reinforced Polymer) are being increasingly used as CC (Crush Cans) due to their higher specific energy absorption capacity in the automotive domain for absorbing impact energy during a frontal crash. Finite element analysis (FEA) based computational methods have matured over the years with increased accuracy and acceptable correlation with experimental results. FEA-based computational studies when used appropriately can reduce the number of physical tests and prototypes required besides accelerating the overall cycle design time. The present work proposes an FEA based design validation approach for the evaluation of post-tensioned crush can design that can absorb more impact energy compared to a normal CFRP thin tube. The FEM based method uses a combination of multiple simulation techniques to predict the behavior of a post-tensioned tube. The post-tensioning in the present work has been proposed in the form of internal pressure for the thin tube. It was found that a safe value of pressure, when applied as a post-tensioning load, can improve the energy absorption capacity without increasing the weight of the tube.

Improving the energy absorption capacity of square CFRP tubes with cutout by introducing chamfer

2021 ◽  
Vol 189 ◽  
pp. 105994
Author(s):  
Zhibo Song ◽  
Shizhao Ming ◽  
Tong Li ◽  
Kaifan Du ◽  
Caihua Zhou ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Absorption Capacity ◽  
Energy Absorption Capacity ◽  
Cfrp Tubes

Full-Scale Testing and Performance Evaluation of Rockfall Concrete Barriers

2015 ◽  
Vol 2522 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Anil Patnaik ◽  
Abdisa Musa ◽  
Srikanth Marchetty ◽  
Robert Liang
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Impact Loading ◽  
Structural Integrity ◽  
Precast Concrete ◽  
Absorption Capacity ◽  
Full Scale ◽  
Energy Absorption Capacity ◽  
Single Impact ◽  
Concrete Barriers

Rockfall hazards are present throughout the state of Ohio. The Ohio Department of Transportation (DOT) employs Test Level 3 standard concrete barriers along the edges of roadways to contain rockfalls in high-risk areas. The performance of these barriers under impact from rocks on the ditch side and their effectiveness for rockfall catchment are relatively unknown. Full-scale impact tests were performed on concrete barriers to simulate the effects of impacts from rocks of various sizes and shapes. Numerous impacts were made at different sections and levels of the barriers to test their structural integrity and energy absorption capacity. The results from this study revealed that 32-in.-high precast concrete barriers with current Ohio DOT details had an impact energy absorption capacity of up to 24 kJ under a single impact. The corresponding energy absorption capacity of 42-in.-high cast-in-place concrete barriers was about 56 kJ under a single impact. Moreover, these barriers experienced severe cracking and spalling of concrete under impact loading. Several design modifications were studied in this test program. These modifications included reducing the spacing of rebars and rebar sizes, using welded wire fabric, and using different types of fibers in the concrete. The tests conducted on the modified concrete barriers showed an impact energy increase of more than 100% with the modifications suggested in this study. Barriers made from the modified designs also experienced significantly reduced extent and severity of cracking and a reduction in spalling and splashing of concrete under impact loading.

Crashworthiness analysis of cylindrical tubes with coupling effects under quasi-static axial loading: An experimental and numerical study

2021 ◽  
pp. 146442072110533
Author(s):  
Hassan Mansoori ◽  
Ramin Hamzehei ◽  
Soheil Dariushi
Keyword(s):  
Energy Absorption ◽  
Poisson’S Ratio ◽  
Absorption Capacity ◽  
Negative Stiffness ◽  
Poisson's Ratio ◽  
Energy Absorption Capacity ◽  
Element Analysis ◽  
Assembly Method ◽  
Cylindrical Tubes ◽  
Force Displacement

In most cylindrical tubes, the occurrence of negative stiffness under compression is unavoidable. This downward trend in the force–displacement relationship means a decrease in the energy-absorption capacity. To this end, this paper introduces a new assembly method comprising two concentric cylindrical tubes. The inner cylinder possesses positive Poisson's ratio behavior, whereas the outer cylinder exhibits negative Poisson's ratio behavior. When compressed, the outer and inner cylinders shrink and expand, respectively, creating surface contacts between the two cylinders, called coupling effects. This property not only avoids the occurrence of negative stiffness in outer cylindrical tube, but also increases the energy-absorption capacity in an upward trend in the force–displacement relationship. To confirm this claim, three different types of cylindrical tubes, possessing positive Poisson’s ratio, zero Poisson's ratio, and negative Poisson’s ratio behaviors, are considered. A finite-element analysis is implemented to simulate deformation patterns of cylindrical tubes. Then, to verify the results of finite-element analysis, a laser-cutting method is applied to fabricate cylindrical tubes from stainless steel tubes. The results show that the proposed assembly method increases the energy-absorption capacity by up to 95% compared to the well-known auxetic tube. Next, a parametric study is performed, in which the gap space between the two cylinders is considered as a design variable. The results reveal the smaller the gap space, the higher the energy-absorption capacity. The absorbed energy in the assembled cylinders without gap space is 17.6 J, which is 36% greater than that of cylinders with 13 mm gap space. The effects of relative density and crushing speed are also evaluated. When compared to the crushing speed, the energy-absorption capacity is highly dependent on relative density.

Effect of Graphene Platelets/Fiber on Plastics Nanocomposites under Low-Velocity Impact Response

2016 ◽  
Vol 852 ◽  
pp. 23-28
Author(s):  
S. Subha ◽  
Battu Sai Krishna ◽  
Dalbir Singh ◽  
R. Gokulnath
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Laminate Plate ◽  
Absorption Capacity ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Energy Absorption Capacity ◽  
Velocity Impact ◽  
The Impact

In this study, an attempt has made to explore the low-velocity impact response of a Carbon/epoxy laminate (CFRP) and E-Glass/epoxy laminates (GFRP). The composite was reinforced with Graphene Nanoplatelets (GnPs) and impact energy absorption capacity was studied. The plain GFRP and plain CFRP were served as a baseline for comparison. These composite laminate plates were fabricated using hand layup technique. The tests were carried out on the laminate plate as per ASTM D5628 FD. Impact tests were performed using a specially designed vertical drop-weight testing machine with an impactor mass of 1.926 kg. The result shows that laminate plate reinforced with GnPs reinforcement enhances the impact energy absorption capacity of the composites almost 4.5 % in the case Carbon/epoxy laminate and 3.5 % in the case of and E-glass/epoxy laminate. The enhanced impact resistance could be attributed to increased interlaminar fracture toughness of the fibres.

ENERGY ABSORPTION OF EXPANSION TUBE CONSIDERING LOCAL BUCKLING CHARACTERISTICS

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5993-5999 ◽  
Author(s):  
KWANG-HYUN AHN ◽  
JIN-SUNG KIM ◽  
HOON HUH
Keyword(s):  
Energy Absorption ◽  
Local Buckling ◽  
Expansion Ratio ◽  
Absorption Capacity ◽  
Buckling Load ◽  
Expansion Tube ◽  
Absorbed Energy ◽  
Energy Absorption Capacity ◽  
Element Analysis ◽  
Numerical Result

This paper deals with the crash energy absorption and the local buckling characteristics of the expansion tube during the tube expanding processes. In order to improve energy absorption capacity of expansion tubes, local buckling characteristics of an expansion tube must be considered. The local buckling load and the absorbed energy during the expanding process were calculated for various types of tubes and punch shapes with finite element analysis. The energy absorption capacity of the expansion tube is influenced by the tube and the punch shape. The material properties of tubes are also important parameter for energy absorption. During the expanding process, local buckling occurs in some cases, which causes significant decreasing the absorbed energy of the expansion tube. Therefore, it is important to predict the local buckling load accurately to improve the energy absorption capacity of the expansion tube. Local buckling takes place relatively easily at the large punch angle and expansion ratio. Local buckling load is also influenced by both the tube radius and the thickness. In prediction of the local buckling load, modified Plantema equation was used for strain hardening and strain rate hardening. The modified Plantema equation shows a good agreement with the numerical result.

scholarly journals Impact Energy Consumption of High-Volume Rubber Concrete with Silica Fume

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Hai-long Li ◽  
Ying Xu ◽  
Pei-yuan Chen ◽  
Jin-jin Ge ◽  
Fan Wu
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Energy Absorption ◽  
Silica Fume ◽  
Impact Energy ◽  
Impact Resistance ◽  
Absorption Capacity ◽  
Rubberized Concrete ◽  
Energy Absorption Capacity ◽  
Fine Aggregates

Adding rubber to concrete aims to solve the environmental pollution problem caused by waste rubber and to improve the energy absorption and impact resistance of concrete. In this paper, recycled rubber particles were used to replace fine aggregates in Portland cement concrete to combine the elasticity of rubber with the compression resistance of concrete. Fine aggregates in the concrete mixes were partially replaced with 0%, 20%, 40%, and 60% rubber by volume, and the cement in the concrete mixes was replaced with 0%, 5%, and 10% of silica fume by mass. The properties of the concrete specimens were examined through compressive strength, splitting tensile strength, flexural loading, and rebound tests. Results show that the compressive strength of concrete and the splitting tensile strength decreased to 11.81 and 1.31 MPa after adding silica fume to enhance the strength 37.8% and 23.7%, respectively, and the dosage of rubber was 60%. With the addition of rubber, the impact energy of rubberized concrete was 2.39 times higher than that of ordinary concrete, while its energy absorption capacity was 9.46% higher. The addition of silica fume increased its impact energy by 3.06 times, but the energy absorption capacity did not change significantly. In summary, the RC60SF10 can be used on non-load-bearing structures with high impact resistance requirements. A scanning electron microscope was used to examine and analyze the microstructural properties of rubberized concrete.

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