دانلود رایگان مقاله لاتین جذب انرژی فوم از سایت الزویر
عنوان فارسی مقاله:
تقویت پر کننده دستگاه های جذب انرژی فوم پر با استفاده از پرتوهای CFRP
عنوان انگلیسی مقاله:
Filler strengthening of foam-filled energy absorption devices using CFRP beams
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
Crashworthiness involves the absorption of energy through controlled failure mechanisms and modes that enable the sustainability of a stable load-time profile during the post-crushing stage. The ability to tailor composites’ properties, in addition to their attributes of high stiffness-to-weight and strength-to-weight ratios, fatigue resistance, and corrosion resistance, makes them extremely attractive in crashworthiness applications. The challenge is to use specific features of geometry and materials to enable greater safety while simultaneously decreasing weight without negatively affecting the overall economics of fabrication and production. However, the effective design of these energy absorbers is a complex undertaking due to the complexity of the multiple concurrent failure modes and their interactions [1–6]. Assessment of the crushing response of composites requires detailed information about the load-displacement history. In general, composite structures show linear and then almost linear load-displacement profiles. This profile is maintained until a certain limit, at which point the load carrying capacity of the structure suddenly drops. The load at which the first peak appears on the load-displacement plot is defined as the peak load (Pi). After the first peak, the plot fluctuates to peaks and valleys before reaching the final densification. The average load reading between the first drop and the final densification represents the mean crushing load (Pm). A smaller difference between the peak and the mean crushing forces reflects greater safety and comfort for the passenger (assuming an emergency case in transportation) and a smoother damage process. The ratio between the mean crushing load and the peak load defines the crush force efficiency (CFE = Pm/Pi), and the desired value of the CFE is unity. To assess the difference in the two load values and the fluctuations during the post-crushing stage, the crush load stability is used (CLS = CFE(1 COV), where COV is the coefficient of variation of the load readings with respect to its mean crushing load). Several factors contribute to the crashworthiness characteristics of laminated composites structures [7]. Among these factors, the geometry of the energy absorption devices plays an important role [8,9]. Palanivelu et al. [10] studied the response of glass fiber– reinforced polyester composite tubes with different geometries. Foam-filled structures were examined by the same authors in [11]. The results of their work showed that the load capacity, crushforce efficiency, and energy absorption are highly affected by the specimen geometry and filler. The improvements obtained by radially stiffening composite tubes were introduced in [12]; the results showed that reinforcing circular tubes with radial GFRP webs improved the load carrying capacity, specific energy absorption, and stability during the post-crushing stage. In addition, the use of hexagonal and octagonal CFRP tubes inside the energy absorption device was introduced for both unfilled and foam-filled rectangular carbon/epoxy [13] and aramid/epoxy [14] composite tubes. Configurations with closed cells are advantageous in terms of the peak and average crushing load, as well as energy absorption, whereas open cells are of great interest when comparing the stability of the crushing load in the post-crushing stage. At the same geometry, the fiber material and orientation highly affects the crashworthiness properties. These effects can be seen in the results obtained by Esnaola et al. [15] for the semi-hexagonal cross-section with glass and basalt fibers. The effect of the fiber orientation on the energy can also be shown in the work done by Hu et al. [16] under the quasi-static and the impact tests. The Energy absorbed in quasistatic crushing was similar to the once obtained by impact crushing. This validates the conclusions resulted by quasi-static tests. Xu et al. [17] also compared the energy absorption of composites specimens under quasi-static and the dynamic crushing tests. The results showed that the difference between them is 15%, which also supported using the quasi-static test. In the same study, the authors presented a comparison between the hybridization scheme of carbon, glass and aramid fibers. The composite specimen, mostly, failed in a brittle fracture mode under crushing, independent of the test condition or the fiber orientation, as it was observed by Wang et al. [18]. The results of that paper showed that, unlike the fracture mode, the energy absorption capability could be improved by selecting proper fiber orientation and wall thickness. As energy absorbers, rectangular sections are extensively used in automotive structures. In the current paper, commercially available carbon/epoxy tubes are used. Rectangle tubes of 1 2 crosssections, I beams and hat sections were arranged in different con- figuration to fill in the rectangle tube 2 4. All of the configurations were then filled with foam. The materials adopted for all of the cross-sections were CFRP composites. The specimens were tested under quasi-static lateral crushing up to final densification.
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کلمات کلیدی:
ENERGY ABSORPTION OF FOAM-FILLED STEEL EXTRUSION ... www.academia.edu/.../ENERGY_ABSORPTION_OF_FOAM-FILLED_STEEL_EXT... Keywords: foam-filled structures, polyurethane foam, energy absorption, .... σ is found to be well fitted with power-law of strengthening equation (4) [21]: σ = Kρ n ... Experimental and Numerical Investigation of Crash Structures Using ... https://books.google.com/books?isbn=3867275424 Hamidreza Zarei - 2008 To compare the strengthening effects of the honeycomb and the foam materials, the ... Therefore, in this case the energy absorption of the foam-filled tube is 6.2 ... Proceedings of Mechanical Engineering Research Day 2015: https://books.google.com/books?isbn=9670257514 Mohd Zulkefli Bin Selamat; Reduan Bin Mat Dan; Abd Rahman Bin Dullah; Abd Salam Bin Md Tahir; Abdul Munir Hidayat Syah Lubis; Abdul Talib Bin Din; Ahmad Anas Bin Yusof; Ahmad Kamal Bin Mat Yamin; Ahmad Rivai; Aliza Binti Che Amran; Azma Putra; Cheng See Yuan; Chong Shin Horng; Faiz Redza Bin Ramli; Fatimah Al-Zahrah Binti Mohd Sa'at; Herdy Rusnandi; Hilmi Bin Amiruddin; Imran Syakir Bin Mohamad; Mariam Binti Md Ghazaly; Md Isa Bin Ali; Md. Fahmi Bin Abd. Samad @ Mahmood; Md Radzai Bin Said; Mohd Ahadlin Bin Mohd Daud; Mohd Asri Bin Yusuff; Mohd Azli Bin Salim; Mohd Azman Bin Abdullah; Mohd Fadzli Bin Abdollah; Mohd Haizal Bin Mohd Husin; Mohd Juzaila Bin Abd. Latif; Mohd Khairi Bin Mohamad Nor; Mohd Nizam Bin Sudin; Mohd Rizal Bin Alkahari; Mohd Zaid Bin Akop; Nona Merry Merpati Mitan; Nor Azmmi Bin Masripan; Norasra Binti A.Rahman; Noreffendy Bin Tamaldin; Nur Rashid Bin Mat Nuri @ Md Din; Omar Bin Bapokutty; Rafidah Binti Hasa; Rainah Binti Ismail; Roszaidi Bin Ramlan; Safarudin Gazali Herawan; Shamsul Anuar Bin Shamsudin; Siti Hajar Binti Sheikh Md. Fadzullah; Siti Nurhaida Binti Khalil; Sivakumar A/L Dhar Malingam; Sushella Edayu Binti Mat Kamal; Tan Chee Fai; Tee Boon Tuan; Umar Al-Amani Bin Haji Azlan; Zairulazha Bin Zainal; Zakiah Binti Halim - 2015 By referring to Figure 4, the energy absorbed by the specimens is obtained by ... Guden, “Predicting energy absorption in a foam-filled thin-walled aluminium tube based on experimentally determined strengthening coefficient”, Mater Des, vol. Experimental and Simulation Study of Energy Absorption Capability of ... https://books.google.com/books/.../Experimental_and_Simulation_Study_of_Ene.html?i... The peak force and energy absorption of foam-filled honeycomb are analyzed ... Therefore, it seems that the foam only plays a role to strengthen the cell walls of ... Sebaey, T.A. and Mahdi, E. (2017) Filler Strengthening of Foam-Filled ... www.scirp.org/(S(vtj3fa45qm1ean45vvffcz55))/reference/ReferencesPapers.aspx?... Jan 16, 2017 - Sebaey, T.A. and Mahdi, E. (2017) Filler Strengthening of Foam-Filled Energy Absorption Devices Using CFRP Beams. Composite Structures ...
