scholarly journals BENDING AFTER IMPACTKOMPOSIT SANDWICH BERPENGUAT SERAT BAMBU-FIBERGLASS DENGAN COREPOLYURETHANE RIGID FOAM

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Agus Dwi Catur ◽  
S. Sinarep ◽  
Paryanto Dwi Setyawan ◽  
Achmad Zainuri ◽  
S. Supriadi
Keyword(s):  
Impact Energy ◽  
Bending Strength ◽  
Laminated Composite ◽  
Rigid Foam ◽  
Composite Sandwich ◽  
Drop Weight ◽  
Reinforcing Fibers ◽  
Weight Impact ◽  
Glass Reinforcement ◽  
The Impact

Impact of the composite sandwich made of materials that become defect, how defects after impact  in material need to be examined .Is that defected composites and wich still has the strength toremain in use?, then the bending after impact strength testing must be done to answer these questions.Composite sandwich with bamboo fiber-fiber glass reinforcement and with a core of 25mm rigid polyurethane foam sheet was produced. Composite sandwich made with two composite sandwich laminate as skinflanking the core. Laminated composite sandwich in this study varied number of layers of reinforcing fibers and type of fiber. Specimens subjected to drop weight impact with varying energy then defect researched and bending  after impact strengthtested. Defects formed on the composite experiencing a drop weight impact loads are: delamination, basin and through hole. The more layers of reinforcing fibers in the composite skin causing moreshallowbasinformed by theresidualimpact. The greater the impact energy causes greater depth of residual basin. Composite sandwich still has the bending strength after impact. Residual bending strength decreases with increasing impact energy imposed on the composite.

Drop Weight Impact Analysis of Laminated Polyurethane Foam/Cloisite 30B Clay

2013 ◽  
Vol 594-595 ◽  
pp. 1089-1093
Author(s):  
Z. Firuz ◽  
Hazizan Md Akil ◽  
Ahmad Sahrim ◽  
Rozaidi Rasid ◽  
S.A. Syed Nuzul Fadzli
Keyword(s):  
Polyurethane Foam ◽  
Impact Force ◽  
Laminated Composite ◽  
Drop Height ◽  
Clay Particles ◽  
Pu Foam ◽  
Drop Weight ◽  
Cloisite 30B ◽  
Weight Impact ◽  
The Impact

Laminated polyurethane foam composite was produced by incorporating Cloisite 30B clay as filler and aluminium sheet as the skin. Initially, PU foams were synthesized with reaction of natural oil polyol and isocyanate with ratio of 1:1.1 by weight. Water was used as the blowing agent and appropriate surfactant and catalyst were added to ensure better performance of end product. Cloisite 30B was added as filler and the percentages were varied from 1 to 5 wt%. Al skin was attached at the top and bottom of the foam to increase the stiffness of the composite and improve its mechanical properties. In order to evaluate its impact characteristic, drop weight impact test was done and the drop height was varied from 5 cm to 20 cm. The results showed that there was no pattern that exists in the impact force, but found the results for the control PU foam (PU foam without filler) has a high impact force values at 5cm, 10 cm and 15 cm drop heights. The incorporation of clay particles were found to give lower impact force to the sample, especially at low filler percentage of 1%. It was found that the addition of clay particles has decrease the impact force of PU foam due to brittleness. Besides, the impact force of the laminated composite is higher than PU foam at the same drop height. For laminated composite at 10 cm, the impact force is higher with an average value of 817% as compared to PU foam. This shows that the addition of Al sheets have improved mechanical characteristics of foam and its ability to withstand higher impact force.

The effect of microwave pretreatment on impact crushing of lead-zinc ore

2021 ◽  
Vol 118 (5) ◽  
pp. 501
Author(s):  
Yulong Liu ◽  
Dexin Ding ◽  
Wenguang Chen ◽  
Nan Hu ◽  
Lingling Wu ◽  
...  
Keyword(s):  
Energy Input ◽  
Impact Test ◽  
Characteristic Parameters ◽  
Microwave Pretreatment ◽  
Drop Weight ◽  
Lead Zinc ◽  
Weight Impact ◽  
Impact Crushing ◽  
The Impact ◽  
The Relationship

The relationship between energy input and particle size of ore samples after crushing and effect of microwave pretreatment on impact crushing of lead-zinc ore were studied by drop weight impact test. The results showed that the lead-zinc ore became softer and had higher degree of crushing after microwave pretreatment. Compared with continuous microwave pretreatment, pulsed microwave pretreatment could improve the drop weight impact crushing efficiency of lead-zinc ore. When the specific comminution energy were 5 kW h/t, 10 kW h/t respectively, the crushing characteristic parameters t10 were 60.42% and 67.46% respectively by continuous microwave. But the values of t10 were increased to 68.64% and 75.88% respectively after pulsed microwave radiation under same microwave power and time. In addition, water quenching could more promote the impact crushing efficiency of lead-zinc ore after microwave irradiation.

scholarly journals Experimental Investigation on the Impact Resistance of Carbon Fibers Reinforced Coral Concrete

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4000 ◽  
Author(s):  
Bing Liu ◽  
Jingkai Zhou ◽  
Xiaoyan Wen ◽  
Jianhua Guo ◽  
Xuanyu Zhang ◽  
...  
Keyword(s):  
Weibull Distribution ◽  
Carbon Fibers ◽  
Impact Test ◽  
Concrete Strength ◽  
Impact Resistance ◽  
Initial Crack ◽  
Drop Weight ◽  
Weight Impact ◽  
The Impact ◽  
Two Parameter

In this study, the impact resistance of coral concrete with different carbon fiber (CF) dosages subjected to drop-weight impact test was investigated. For this purpose, three concrete strength grades (C20, C30, C40) and six CF dosages (0.0%, 0.3%, 0.6%, 1.0%, 1.5%, and 2.0% by weight of the binder) were considered, and a total of 18 groups of carbon fibers reinforced coral concrete (CFRCC) were cast. For each group, eight specimens were tested following the drop-weight impact test suggested by CECS 13. Then, the two-parameter Weibull distribution theory was adopted to statistically analyze the variations in experimental results. The results indicated that the addition of CFs could transform the failure pattern from obvious brittleness to relatively good ductility and improve the impact resistance of coral concrete. Moreover, the impact resistance of CFRCC increases with the CF dosage increasing. The statistical analysis showed that the probability distribution of the blow numbers at the initial crack and final failure of CFRCC approximately follows the two-parameter Weibull distribution.

Effect of specimen size and ball size on breakage throughput in the drop-weight test

2018 ◽  
Vol 233 (2) ◽  
pp. 202-210 ◽  
Author(s):  
Mehdi Akhondizadeh ◽  
Masoud Rezaeizadeh
Keyword(s):  
Impact Energy ◽  
Specimen Size ◽  
Test Machine ◽  
Ball Size ◽  
Drop Weight ◽  
Weight Test ◽  
Drop Weight Test ◽  
Steel Balls ◽  
The Impact ◽  
Specific Impact

Effects of specimen size and ball size on the breakage throughput under the impact loading are investigated using a drop-weight test machine. Samples are square-shaped building stones ranging 20–60 mm in width and 22–256 g in mass. They include granite, marble, and two types of travertine with the thickness of 15 mm. The impact energies, up to 160 J, are achieved by falling balls in a drop-weight test machine. Several steel balls with the diameter of 60, 84, 96, and 120 mm have been used as an impactor. The ball size is a parameter whose effect on the breakage throughput is investigated here. Results show that the larger specimens have better breakage than the smaller ones at the same specific impact energy. It is also indicated that, at constant specific impact energy, the smaller balls behave more efficiently than the larger balls.

Impact resistance of Nomex honeycomb sandwich structures with thin fibre reinforced polymer facesheets

2016 ◽  
Vol 20 (5) ◽  
pp. 531-552 ◽  
Author(s):  
Longquan Liu ◽  
Han Feng ◽  
Huaqing Tang ◽  
Zhongwei Guan
Keyword(s):  
Finite Element ◽  
Impact Energy ◽  
Sandwich Structures ◽  
Impact Resistance ◽  
Impact Response ◽  
Woven Fabric ◽  
Drop Weight ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb ◽  
The Impact

In order to investigate the impact resistance of the Nomex honeycomb sandwich structures skinned with thin fibre reinforced woven fabric composites, both drop-weight experimental work and meso-mechanical finite element modelling were conducted and the corresponding output was compared. Drop-weight impact tests with different impact parameters, including impact energy, impactor mass and facesheets, were carried out on Nomex honeycomb-cored sandwich structures. It was found that the impact resistance and the penetration depth of the Nomex honeycomb sandwich structures were significantly influenced by the impact energy. However, for impact energies that cause full perforation, the impact resistance is characterized with almost the same initial stiffness and peak force. The impactor mass has little influence on the impact response and the perforation force is primarily dependent on the thickness of the facesheet, which generally varies linearly with it. In the numerical simulation, a comprehensive finite element model was developed which considers all the constituent materials of the Nomex honeycomb, i.e. aramid paper, phenolic resin, and the micro-structure of the honeycomb wall. The model was validated against the corresponding experimental results and then further applied to study the effects of various impact angles on the response of the honeycomb. It was found that both the impact resistance and the perforation depth are significantly influenced by the impact angle. The former increases with the obliquity, while the latter decreases with it. The orientation of the Nomex core has little effect on the impact response, while the angle between the impact direction and the fibre direction of the facesheets has a great influence on the impact response.

scholarly journals 3D Progressive Failure Modeling of Drop-Weight Impact on Composite Laminates

2018 ◽  
Author(s):  
DC Pham
Keyword(s):  
Composite Laminates ◽  
Impact Damage ◽  
Progressive Failure ◽  
Damage Model ◽  
Matrix Cracking ◽  
Structural Level ◽  
Velocity Impact ◽  
Drop Weight ◽  
Weight Impact ◽  
The Impact

Composite laminates are susceptible to out-of-plane impact loads due to the lack of reinforcement in the through-thickness direction. Unlike the localized damage induced by a high velocity impact where the incident energy is dissipated near a contact area, low velocity impact damage involves multiple failure mechanisms such as matrix cracking, fiber breakage, and widespread interface delaminations. Depending on the extent of damage, significant reduction in the load-bearing capability of the structure has been observed. The prediction of composite impact damage resistance by a reliable progressive damage analysis tool is essential to reduce intensive and expensive certification tests at structural level. In this work, an enhanced explicit 3D damage model is implemented via VUMAT in Abaqus to perform a drop-weight impact simulation of a [454/04/-454/904]s Hexply AS4/8552 composite laminate. The impact-induced damage and its extent are captured by a 3D Continuum Damage Model (CDM) coupled with an energy driven failure mechanism. The developed module provides a unified solution process for the impact response prediction followed by the residual strength prediction under compression within an explicit solver. Two examples are selected to demonstrate the capability of the progressive failure analysis under dynamic and static loading: 1) a drop-weight test; and 2) an open-hole tension test. Numerical predictions from the developed VUMAT are compared with the test data and predictions using the open source CompDam code developed by NASA.

Relationship between Impact Energy and Flexural Toughness Energy of Steel Fiber Reinforced Lightweight Aggregate Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 385-388
Author(s):  
Hai Tao Wang ◽  
Jin Qing Jia
Keyword(s):  
Impact Energy ◽  
Impact Resistance ◽  
Lightweight Aggregate ◽  
Steel Fibers ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Flexural Toughness ◽  
Drop Weight ◽  
Flexural Tests ◽  
The Impact

In order to determine the impact resistance of lightweight aggregate concrete (LWC), especially the effect of steel fibers on impact resistance of LWC, a series of drop-weight tests, recommended by the ACI committee 544, have been carried out in the present study. Impact and flexural tests were carried out on lightweight aggregate concrete reinforced with five different percentages of steel fibers 0.0%, 0.5%, 1.0%, 1.5% and 2.0% by volume of concrete. For each volume of fibers, complete load–deflection curves of SFLWC were generated in order to determine the total energy absorbed for each specimen. The addition of steel fibers to concrete has improved impact resistance and also the flexural toughness. The test results showed that a logarithmic relation exists between flexural toughness energy by means of the generated load–deflection curves from the flexural tests and the impact energy by means of drop-weight tests.

scholarly journals Analysis of Impact Characteristics and Detection of Internal Defects for Unidirectional Carbon Composites with Respect to Fiber Orientation

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 203
Author(s):  
Sun-ho Go ◽  
Alexandre Tugirumubano ◽  
Hong-gun Kim
Keyword(s):  
Carbon Fiber ◽  
Impact Test ◽  
Carbon Fiber Composites ◽  
Internal Defects ◽  
Impact Tests ◽  
Drop Weight ◽  
Weight Impact ◽  
Fibers Orientation ◽  
Lock In ◽  
The Impact

With the increasing use of carbon fiber reinforced plastics in various fields, carbon fiber composites based on prepregs have attracted attention in industries and academia research. However, prepreg manufacturing processes are costly, and the strength of structures varies depending on the orientation and defects (pores and delamination). For the non-contact evaluation of internal defects, the lock-in infrared thermography was proposed to investigate the defects in the composites subjected to the compression after impact test (CAI). The drop-weight impact test was conducted to study the impact behavior of the composites according to fibers orientation for composite fabricated using unidirectional (UD) carbon fiber prepregs. Using CAI tests, the residual compressive strengths were determined, and the damage modes were detected using a thermal camera. The results of the drop weight impact tests showed that the specimen laminated at 0° suffered the largest damage because of susceptibility of the resin to impact. The specimens with 0°/90° and +45°/−45° fibers orientation exhibited more than 90% of the impact energy absorption and good impact resistance. Furthermore, the specimens that underwent the impact tests were subjected to compressive test simultaneously with the lock-in thermography defects detection. The results showed that internal delamination, fibers splitting, and broken fibers occurred. The temperature differences in the residual compression tests were not significant.

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