A failure analysis study on the fractured connecting bolts of a filter press

Molaei, Sh.; Alizadeh, Reza; Attarian, M.; Jaferian, Y.

doi:10.1016/j.csefa.2015.07.003

Cited by 20 publications

(4 citation statements)

References 19 publications

(20 reference statements)

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“…Failure of bolts and bolted connections occurs in different types of structures, like steel concrete composite beams (Zhang et al, 2019), beam to column assemblies (Grimsmo et al, 2016), filter press (Molaei et al, 2015), helicopter gearbox support strut (Krstic et al, 2016), compressor (Zhu et al, 2017), Francis turbine (Casanova and Mantilla, 2018) and submersible pump (Escobar et al, 2016). Failure investigations show different types of fracture mechanisms static shear and bending (Zhang et al, 2019) or tensile (Grimsmo et al, 2016), fatigue (Molaei et al, 2015;Zhu et al, 2017;Casanova and Mantilla, 2018) and stress corrosion cracking (Krstic et al, 2016;Escobar et al, 2016).…”

Section: Structural Integritymentioning

confidence: 99%

Rainwater propeller pumps structural integrity

Galatanu

Muntean

Marșavina

et al. 2019

IJSI

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Purpose The purpose of this paper is to focus on the structural integrity of the rainwater propeller pumps installed in the municipal wastewater treatment plant (WTP). Design/methodology/approach A numerical analysis is performed to determine the maximum shear stress on the fasten bolts. The rainwater propeller pump is examined in operation at normal conditions and when one blade is progressively blocked. Findings The failure mechanism of the rainwater pump impeller is determined. Research limitations/implications The fibbers and wastes are discharged together with rainwater during storms with these types of pumps to avoid the flood of the WTP. Several catastrophic events have occurred in service due to the fibbers clog the gap between the impeller blades and the pump casing. The clogging process is partially understood so actual technical solutions deal with effects rather the main causes. Practical implications The operation time of all seven rainwater pumps installed in Timisoara’s WTP is investigated. Climate changes in Banat region and new waste properties found in the wastewater require appropriate technical solutions. A technical solution is proposed based on these investigations to extend the operation time and to diminish the operation and maintenance costs. Social implications These large pumps are installed in the urban sewage centralised system implemented in the most cities. The access to the sewerage network is a requirement of any community, regardless of the social status. Originality/value The fracture surfaces of both fastening bolts of the rainwater pump impellers produced in service are examined. As a result, it has been identified that the catastrophic events are due to the brittle fracture of both fasten bolts between the impeller blades and the pump hub, respectively. The catastrophic events of the rainwater propeller pumps are directly correlated to the clog level of the impeller. The numerical simulation is performed to determine the maximum shear stress on the fasten bolts. The case with pump operating at normal conditions is performed identifying its vulnerabilities to clog conditions. Next, one impeller blade is progressively blocked considering three time stop scenarios associated with different clog levels. Conclusively, the operating time of the rainwater pump up to the catastrophic failure is correlated to the clog level of the impeller.

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Section: Structural Integritymentioning

confidence: 99%

Rainwater propeller pumps structural integrity

Galatanu

Muntean

Marșavina

et al. 2019

IJSI

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“…Para peneliti dan praktisi telah melakukan beberapa analisa mengenai kegagalan sambungan baut-mur untuk berbagai aplikasi. Dari beberapa contoh yang ada, sebagian besar studi berpusat pada kegagalan pada baut yang termasuk pada kategori patah lelah [4,5].…”

Section: Pendahuluanunclassified

Investigasi Fraktografi Dan Analisa Tegangan Pada Kerusakan Baut M64 Grade 10,9 Yang Mengalami Pengencangan Berlebih

Ihlas

Puspita

Tjahjohartoto

2018

JTBBT

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Baut dengan dimensi yang relatif besar umum digunakan pada infrastrukur, misalnya di pelabuhan. Telah dilakukan investigasi kerusakan pada baut M64 Grade 10,9 yang mengalami patah antara bagian kepala dan batang. Tujuan penelitian ini adalah untuk mengetahui penyebab kerusakan agar kejadian serupa tidak terulang kembali. Oleh karena itu, dilakukan serangkaian pengujian, pemeriksaan, dan perhitungan terhadap tegangan yang bekerja. yaitu (1) pemeriksaan visual dan fraktografi, (2) pengujian komposisi kimia, dan (3) perhitungan analisa tegangan. Hasil penelitian memperlihatkan bahwa sebagian besar permukaan patah didominasi oleh indikasi daerah beban berlebih (zona overload) yang menunjukkan patah getas dan terjadi seketika. Hal ini dibuktikan dengan ditemukan beberapa ratchet mark yang merupakan tipikal adanya konsentrasi tegangan. Kondisi ini sangat sensitif terhadap beban tarik pada saat pengencangan. Berdasarkan analisa permukaan patahan termasuk kategori menerima kombinasi beban tarik dan bending yang terkonsentrasi. Sedangkan berdasarkan perhitungan analisa tegangan membuktikan bahwa telah terjadi beban torsi berlebih (over-torquing) yang diterima oleh baut.Kata kunci: baut, konsentrasi tegangan, fraktografi, ratchet mark

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“…However, most reported bolt fractures occur in the bolt bar, and the finite element model always simplifies the bolt as a bar with a fixed diameter. The thread was ignored in most previous studies, leading to a lack of understanding of thread failure, especially the effect of thread damage on the bolt fracture [20]. Indeed, the fracture of high-lock bolts during assembly mostly occurs in the thread because of the large pre-tightening force and its small size.…”

Section: Introductionmentioning

confidence: 99%

Fracture Mode Transition during Assembly of TC4 High-Lock Bolt under Tensile Load: A Combined Experimental Study and Finite Element Analysis

Feng¹,

Dong²,

Hu³

et al. 2022

Materials

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Fracture during the assembly process is an important failure mode for high-lock bolts used in the aviation industry, which greatly increases the potential of unpredictable accidents during service. In the current study, the underlying reasons for fracture during the assembly of a TC4 high-lock bolt was investigated using a tensile test and finite element analysis (FEA). The microstructure of the as-received bolt consisted of a high proportion of α phase, some β phase, and a small amount of α′ phase formed via martensite phase transformation during the rammer process. The experimental force–displacement curves revealed an average yield load of 55.9 kN and a breaking load of 67.65 kN. The corresponding yield strength was calculated to be 0.9 GPa, which was smaller than the standard value of TC4. This was attributed to the preload-induced stress concentration on the thread surface, leading to obvious strain hardening, which can lead to crack initiation. The effect of preload was further confirmed by the fractographies in which the initial crack was observed on the thread surface. The fractographies suggested that hybrid fracture occurred on the tensile loaded bolt. The initial failure was brittle fracture on the thread surface, transforming into ductile fracture in the screw. The results can contribute to understanding the effect of preload on the load carry capacity of high-lock bolts and provide a strategy to design its assembly specification.

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A failure analysis study on the fractured connecting bolts of a filter press

Cited by 20 publications

References 19 publications

Rainwater propeller pumps structural integrity

Rainwater propeller pumps structural integrity

Investigasi Fraktografi Dan Analisa Tegangan Pada Kerusakan Baut M64 Grade 10,9 Yang Mengalami Pengencangan Berlebih

Fracture Mode Transition during Assembly of TC4 High-Lock Bolt under Tensile Load: A Combined Experimental Study and Finite Element Analysis

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