Tailor-made design, fabrication and validation of SrO doped nanostructured ZTA ceramic Femoral head – Acetabular socket liner assembly Shaik Akbar Basha, Ashish Kumar Agrawal, Debasish Sarkar Journal of the Mechanical Behavior of Biomedical Materials, 2021 An established commercial grade SrO doped ZTA composition has been considered to design, fabrication through uniaxial pressing followed by sintering and polishing, validation of dimension, 3D surface profile, 3D microstructure, and compressive load bearing capacity of femoral head - acetabular socket liner prototypes for the hip prosthesis. While design and dimensions are concerned, both the steel (HRC60) molds were designed and machined to achieve precious dimensions of femoral head (FH; OD - 30 ± 0.01 mm) and acetabular socket liner (ASL; ID - 30.15 ± 0.01 mm). A close variation in the range of ±0.01 mm was confirmed the precision geometry of polished FH and ASL with consideration of 22 points coordinate measuring method (CMM). 3D surface profile ensures the surface characteristics of Ra = 0.2 ± 0.01 μm and Rq = 0.5 ± 0.01 μm for outer surface of FH and an inner surface of ASL, respectively. Structure integrity and fabrication defects including cracks and pores free bulk structures were confirmed by Micro CT. The compressive load resistance known as burst strength for independent FH and FH-ASL assembly were measured 16.2 KN and 17.6 KN, respectively. The developed ceramic prototypes have an economic advantage and can be adopted as artificial hip prosthesis after extensive in-vitro and in-vivo analysis.
Critical load and wear regime of hydrothermal-aged SrO-doped ZTA composite Shaik Akbar Basha, Debasish Sarkar International Journal of Modern Physics B, 2021 The research work has demonstrated the effect of hydrothermal ageing ([Formula: see text]C, 40 h, 1.034 bar) on friction and wear behavior of SrO-doped zirconia toughened alumina (ZTA) composite. Surface topography and wear regime behavior are established in the perspective of ageing time, load, phase transformation and toughening phenomena. The estimated critical load is confirming the expedition of mild to severe wear in the presence of microcrack formation during adhesive and abrasive wear between SrO-doped ZTA (disc) and ZrO2 (ball) tribo couples, where adhesion between the SrO–ZTA disc and ZrO2 ball results in transfer of ZrO2 particles from ball to disc. Roughness parameters ([Formula: see text], [Formula: see text]) are elucidated to understand the influence of load and ageing conditions, as well as the in vitro bioactivity of sintered specimens is assessed in simulative body fluid (SBF) solution.
Salient features of SrO doping in Al2O3 – 5 wt.% ZrO2 reaction sintered composite ceramics Shaik Akbar Basha, K. Sarath Chandra, Debasish Sarkar Journal of Alloys and Compounds, 2020 SrO doping (concentration range ≈ 5000 ppm) in Al2O3–5 wt.% ZrO2 ceramic system offers the unique features of reaction sintering to produce dense composite ceramics of finer sized matrix grains with nearly homogeneous multiphase microstructures for improving the room-temperature structural properties (e.g. hardness, strength, and toughness). Reaction sintered product, the strontium hexaluminate (SrAl12O19) forms in-situ as an interphase boundary in the ceramic composite during the stages of reaction sintering. This creates new low energy Al2O3/SrAl12O19 chemical interfaces in the matrix of alumina. Typical issues based on prominent role of in-situ formed low energy Al2O3/SrAl12O19 interfaces on the properties of reaction sintered composite ceramics (SrO doped Al2O3–5 wt.% ZrO2) are discussed.
Competitive life time assessment of SrO-ZTA/SrO-ZTA and CoCrMo/uhmwpe hip prosthesis bearings SHAIK AKBAR BASHA, DEBASISH SARKAR Journal of Mechanics in Medicine and Biology, 2020 The hip joint envisages the prime load bearing structure among other joints in the human body. Hip joint failure leads to the replacement of the hip joint prosthesis. This research work focuses on the proper selection of bearing couple materials for the hip joint to improve the performance and life. Herein, the stress and deformation of different bearing couple materials are analysed in the perspective of transient dynamic analysis under jogging load cycle. Selective hip joint bearing (femoral head-liner) couples are SS316L on UHMWPE (MoP), CoCrMo on UHMWPE (MoP), Ti6Al4V on SrO-ZTA (MoC), SrO-ZTA on UHMWPE (CoP) and SrO-ZTA on SrO-ZTA (CoC) encountered, respectively. The SrO-ZTA on SrO-ZTA (CoC) bearing couple generates the less Von Mises stress of 180.88 MPa. Load bearing pressure and Archard law predict the wear depth of CoCrMo on UHMWPE (MoP) and SrO-ZTA on SrO-ZTA (CoC) bearing couples are 0.141 mm/year and 0.031 mm/year, respectively. In simultaneous, the theoretical wear volume for CoCrMo on UHMWPE (MoP) and SrO-ZTA on SrO-ZTA (CoC) bearing couples are found as 35.46[Formula: see text]mm3/year and 2.62[Formula: see text]mm3/year, respectively. The wear depth and wear volume are supporting the available clinical retrievals and exist in well acceptable range. Competitive wear analysis data ensures 15 years safe life of SrO-ZTA on SrO-ZTA (CoC) hip prosthesis bearing.
Finite Element Analysis and Theoretical Wear Behaviour for Total Hip Replacement Shaik Akbar Basha, Debasish Sarkar Lecture Notes in Mechanical Engineering, 2020 In consideration of total hip replacement (THR) and theoretical life estimation, we extensively performed finite element analysis and predicted the wear behaviour of different head sizes of 28, 30 and 32 mm and two bearing systems namely ZTA head—ZTA liner and Ti6Al4V head—UHMWPE liner. Static but stance activity was encountered for the 100 kg subject, where the ZTA head—ZTA liner combination exhibit less von mises stress compared to Ti6Al4V head—UHMWPE liner bearing. Interestingly, 30 mm femoral head experiences more jump distance (JD) and more range of motion (ROM) in comparison of the 28 mm femoral head, and less deformation compares to 32 mm femoral head. The wear behaviour is estimated using Archard’s law and predicted wear depth is around 600 µm for 15 years for 30 mm femoral head during articulating motion with identical tribocouple.
Dynamic Analysis and Life Estimation of the Artificial Hip Joint Prosthesis Akbar Basha Shaik, Debasish Sarkar Advances in Intelligent Systems and Computing, 2020 While discussing the hip joint failure, material selection and apposite dimension of the femoral head are a significant concern for the artificial hip replacement. In this context, an attempt was made to optimize both ball head and socket material from different combinations like femoral head (metal)—acetabular liner (Polyethylene) and femoral head (ceramic)—acetabular liner (ceramic) in consideration of a different set of femoral ball head size of 28, 30 and 32 mm. The material and femoral head size were optimized in the perspective of minimum stress that eventually enhances the prosthesis life and minimizes the wear of counter bodies. The hip joint prosthesis was designed in CATIA V5 R17 followed by finite element analysis (FEA) was performed in ANSYS 17.2. Dynamic FEA was performed when the 100 kg human in jogging. A theoretical optimization established the combination of ceramic–ceramic articulating body consists of 30.02 mm ID acetabular liner—30 mm OD femoral head made of zirconia toughened alumina (ZTA) experience less stress and deformation that eventually exhibit very low wear rate per cycle of jogging. This design exhibits 0.93 mm wear depth after 15 years of activity; however, similar theoretical analysis can be done under different degree of dynamic motions. The proposed material and design combination has excellent potential for the development of artificial hip joint prosthesis.
Grain growth suppression of ZTA by multi-step sintering Shaik Akbar Basha, Debasish Sarkar Materials Today Proceedings, 2019 Effect of two-step sintering of Zirconia Toughened Alumina (ZTA) on microstructure and mechanical properties were studied in the present work. Al2O3 and 3YSZ nanoparticles were mixed by high speed vibrating mill, and powders were compacted by a uniaxial pressing protocol at 150 MPa, and sintered through both conventional sintering schedule (CSS) and two-step sintering (TSS) schedules. The composition containing 95 wt% Al2O3 and 5 wt% 3YSZ sintered at two-step sintering (TSS-2; 1600 °C/10 min followed by 1500 °C/6 h) exhibits higher Vickers hardness (1835 HV), fracture toughness (4.95 ± 0.1 MPa.√m), compressive strength (900 MPa) and Diametral tensile strength (125 MPa), respectively. The ZTA composite shows relative density 99.2% with grain size 4.5 µm during CSS at 1600 °C for 4 h. However, the TSS-2 facilitates to achieve relative density 98.4% consist of 1.4 µm alumina grain size that eventually experiences ∼21% fracture toughness increment through zirconia phase assisted transformation toughening.
