Analytical Investigation on Cyclic Response of Buckling-restrained Braces with Short Yielding Core Segments

Muhamed Safeer Pandikkadavath,Dipti Ranjan Sahoo 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.4

Buckling-restrained braced frames (BRBFs) are considered to be one of the efficient lateral force-resisting systems used in buildings located in the seismically active regions. Nearly symmetric hysteretic response of buckling-restrained braces (BRBs) in tension and compression due to the yielding of steel core plates helps the BRBFs to withstand the seismic excitations without causing any extensive damage to the primary frame members. However, BRBFs may exhibit the excessive post-earthquake residual drift response due to the low axial stiffness of BRBs under the strong ground motions. A reduction in the yielding core segments of BRBs results in the improved elastic and post-elastic axial stiffness of BRBs which may help in controlling the excessive residual drift response. This study is focussed on the analytical evaluation of hysteretic response of BRBs of varying lengths using finite element (FE) software. The results of FE study are further used to evaluate the inter-story and residual drift response of a 3-story braced frame fitted with BRBs of short core lengths (referred as SBRBF). Nonlinear dynamic analysis results of SBRBF are compared with the conventional BRBF and concentrically braced frame (CBF). It is concluded that the optimum reduction in yielding core lengths of BRBs can improve the overall seismic response of BRBFs with a reduction in the residual drift response.

Mitigation of seismic drift response of braced frames using short yielding-core BRBs

Muhamed Safeer Pandikkadavath,Dipti Ranjan Sahoo 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.3

Buckling-restrained braced frames (BRBFs) are commonly used as the lateral force-resisting systems in building structures in the seismic regions. The nearly-symmetric hysteretic response and the delayed brace core fracture of buckling-restrained braces (BRBs) under the axial cyclic loading provide the adequate lateral force and deformation capacity to BRBFs under the earthquake excitation. However, the smaller axial stiffness of BRBs result in the undesirable higher residual drift response of BRBFs in the post-earthquake scenario. Two alternative approaches are investigated in this study to improve the elastic axial stiffness of BRBs, namely, (i) by shortening the yielding cores of BRBs; and (ii) by reducing the BRB assemblies and adding the elastic brace segments in series. In order to obtain the limiting yielding core lengths of BRBs, a modified approach based on Coffin-Manson relationship and the higher mode compression buckling criteria has been proposed in this study. Both non-linear static and dynamic analyses are carried out to analytically evaluate the seismic response of BRBFs fitted with short-core BRBs of two medium-rise building frames. Analysis results showed that the proposed brace systems are effective in reducing the inter-story and residual drift response of braced frames without any significant change in the story shear and the displacement ductility demands.

Corporate Investment Behaviour and Monetary Policy: Evidence from Firm-level Data for Malaysia

Muhamed Zulkhibri 연세대학교 동서문제연구원 2013 Global economic review Vol.42 No.3

Using a panel data-set of over 900 listed firms in Malaysia for the period 1991 2010, this paper examines the empirical evidence on the credit channel of the monetary transmission mechanism within the framework of corporate investment. The results suggest that monetary policy significantly impacts the firms’ access to external finance during times of increasing interest rates, in particular, bank-dependent firms are the most vulnerable firms. The firms’ investment sensitivity on external financing explains the relatively underdeveloped capital market and the prominent role played by the banking sector for capital allocation in the Malaysian economy. Internal finance is more important for high leverage firms during tight liquidity conditions.

Penetration testing of 3D printed projectiles made of various types of polymers

Muhamed Bisić,Faruk Razić,Adi Pandžić,Mustafa Bevrnja 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.11

This paper presented an experimental process of penetration testing of FDM 3D printed projectiles made of 5 different types of polymers. Phases of design and 3D printing procedure are described, along with details about materials. Experiment is conducted on an improvised set-up with compressed air used for launching projectiles. Each material was tested with 3 projectiles launched at wooden boards. Muzzle velocity and penetration depth are measured and used for different calculations. Results show interesting and mostly unexpected penetration depth values of different materials. Based on several standards, some of the projectiles can be considered very dangerous and potentially lethal.

Influence of Mn on the Mechanical and Shape Memory Transformation Behaviours of Powder Metallurgy Processed Cu–Al–Ni SMAs

M. Muhamed Shafeeq,Hirshikesh,G. K. Gupta,D. P. Mondal 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.1

In this work, a novel powder metallurgy method comprising elemental powder mixing and hot vacuum compaction wasused to produce fine-grained Cu–Al–Ni–Mn SMA successfully. The effects of Mn (0–3 wt%) addition and different Al concentrationson the mechanical and shape memory capabilities of powder-processed Cu–Al–Ni SMA were investigated. Theformation of different martensitic and secondary phases is characterized by field emission scanning electron microscope,and X-ray diffraction. The addition of Mn improved ductility and decreased phase transformation temperature of the powderprocessedSMA, which was confirmed using a three-point bending/tensile test and differential scanning calorimetry analysis.

In vivo magnetic resonance imaging morphometry of the patella bone in South Indian population

Reshma Muhamed,Vasudha V. Saralaya,B. V. Murlimanju,Ganesh Kumar Chettiar 대한해부학회 2017 Anatomy & Cell Biology Vol.50 No.2

Racial differences exist in the dimensions of structures and the commercially available prostheses are designed based on the Caucasians. In this context, the goal of the present investigation was to determine the gender wise measurements of patella bone in South Indians. The present study included axial magnetic resonance images of the knee joint from 140 South Indian adults (70 males, 70 females; aged between 20–70 years). The angle, width, thickness, lateral facet width, facet thickness, ratio of the lateral facet, the relative thickness and ratio of facet thickness were measured in the patella by using the digital ruler. The statistical analysis was performed by using the SPSS software. The dimensions exhibited statistically highly significant sexual dimorphism (P≤0.001). The mean value was higher in males than females except for the ratio of patellar lateral facet and patellar facet thickness ratio. It was observed that the males exhibit more variability than females in all the measurements of patella except patellar thickness, patellar facet thickness, patellar relative thickness, and patellar facet thickness ratio. The present study of the in vivo morphometry of patella bone from the South Indians can provide a population and gender specific database for the morphometric measurements of the patella. We believe that the data of the present study will be useful to the orthopaedician during the procedures like arthroplasty of the total knee, patellofemoral arthroplasty, resurfacing of patella, and designing the prosthetic implant.

Clogging potential of low-flush toilet branch drain system

Shuaeb, Muhamed Abubakr M.,Han, Mooyoung Taylor Francis 2018 Urban water journal Vol.15 No.1

Prediction of response of reinforced concrete frames exposed to fire

Balaji, Aneesha,Muhamed Luquman, K.,Nagarajanb, Praveen,Pillai, T.M. Madhavan Techno-Press 2016 Advances in computational design Vol.1 No.1

The objective of this work is to study the restraining effect in fire resistance of framed structures and to evaluate the global response of reinforced concrete frames when exposed to fire based on advanced finite element method. To study the response a single portal frame is analyzed. The effect of floor slab on this frame is studied by modeling a beam-column-slab assembly. The evolution of temperature distribution, internal stresses and deformations of the frame subjected to ISO 834 standard fire curve for both the frames are studied. The thermal and structural responses are evaluated and a comparison of results of individual members and entire structure is done. From the study it can be seen that restraining forces has significant influence on both stresses and deflection and overall response of the structure when compared to individual structural member. Among the various structural elements, columns are the critical members in fire and failure of column causes the failure of entire structure. The fire rating of various structural elements of the frame is determined by various failure criteria and is compared with IS456 2000 tabulated fire rating.

Epidemiological Features of Human Cases After Bites/Scratches From Rabies-suspected Animals in Zenica-Doboj Canton, Bosnia and Herzegovina

Selma Uzunović,Muhamed Skomorac,Fatima Bašić,Ivona Mijač-Musić 대한예방의학회 2019 Journal of Preventive Medicine and Public Health Vol.52 No.3

Objectives: To determine the epidemiological features of patients and animals after bites/scratches from rabies-suspected animals in Zenica-Doboj Canton, Bosnia and Herzegovina. Methods: Data from all patients (and the causative animals) admitted to the Antirabies Service of the Institute for Health and Food Safety Zenica in the 2009-2017 period were analyzed, including age, sex, anatomical site of the bite/scratch, animal type (stray/owned/wildlife), veterinary observations of the animal, and whether antirabies post-exposure prophylaxis (PEP) was indicated and/or administered. Results: In total, 1716 patients were admitted. Bites/scratches were most frequently recorded during April and May (n=181, 10.5% and n=163, 9.5%, respectively). The persons admitted were mostly from the Zenica municipality (n=1278, 74.5%; incidence: 11.55/ 1000), which is 66.6% urbanized. Males were more frequently represented (n=1089, 63.6%). The patients were mostly 50-64 and 25-49 years of age (n=425, 24.7% and n=390, 22.7%, respectively). Dog bites were the most common cause (n=1634, 95.1%, of which n=1258, 77.0% were caused by stray dogs). PEP was indicated for 997 (58.1%) patients. Only 340 (19.9%) animals underwent veterinary observations (3.1% of stray and 76.1% of owned animals). The largest number of injuries were presented at lower extremities, 1044 (60.8%) cases. Conclusions: Zenica-Doboj Canton is a rabies-free region. Due to the high rate of stray animals not undergoing veterinary observations, the non-existence of a unique dog registry, and the consequent lack of information about stray animals in terms of number, vaccination, neutering, and euthanasia, there is an urgent need for improving the prevention and control of rabies within the One Health framework.

Association of Spinal Alignment Correction With Patient-Reported Outcomes in Adult Cervical Deformity: Review of the Literature

Elie Massaad,Muhamed Hadzipasic,Ali Kiapour,Asad M. Lak,Ganesh Shankar,Hasan A. Zaidi,Stuart H. Hershman,John H. Shin 대한척추신경외과학회 2021 Neurospine Vol.18 No.3

Objective: Adult cervical deformity (ACD) is a debilitating spinal condition that causes significant pain, neurologic dysfunction, and functional impairment. Surgery is often performed to correct cervical alignment, but the optimal amount of correction required to improve patient-reported outcomes (PROs) are not yet well-defined. Methods: A review of the literature was performed and Fisher z-transformation (Zr) was used to pool the correlation coefficients between alignment parameters and PROs. The strength of correlation was defined according to the following: poor (0<r≤0.3), fair (0.3<r≤0.5), moderate (0.5<r≤0.8), and strong (0.8<r≤1). Results: Increased C2–7 sagittal vertical axis was fairly associated with increased Neck Disability Index (NDI) (pooled Zr=0.31; 95% confidence interval [CI], -0.03 to 0.58). Changes in T1 slope minus cervical lordosis poorly correlated with NDI (pooled Zr=-0.04; 95% CI, -0.23 to 0.30). Increased C7–S1 was poorly associated with worse EuroQoL 5-Dimension (pooled Zr=-0.22; 95% CI, -0.36 to -0.06). Correction of horizontal gaze did not correlate with legacy metrics. Modified Japanese Orthopedic Association correlated with C2-slope, C7–S1, and C2–S1. Conclusion: Spinal alignment parameters variably correlated with improved health-related quality of life and myelopathy after corrective surgery for ACD. Further studies evaluating legacy PROs, Patient-Reported Outcomes Measurement System, and ACD specific instruments are needed for further validation.