Design Process of Low Cost Uncemented Femoral Stem 316L Stainless Steel Using Investment Casting Technique

2016 ◽  
Vol 1133 ◽  
pp. 70-74
Author(s):  
Mohd Yusof Baharuddin ◽  
S. Hussain Salleh ◽  
Alias Mohd Nor ◽  
Muhammad Hisyam Lee ◽  
Ahmad Hafiz Zulkifly ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stainless Steel ◽  
Investment Casting ◽  
316L Stainless Steel ◽  
Femoral Stem ◽  
Von Mises Stress ◽  
Manufacturing Cost ◽  
Element Analysis ◽  
The Finite Element Analysis

Total hip replacement (THR) is a flourishing orthopaedic surgery which generating billion of dollars of revenue. The cost associated with the fabrication of implants has been increasing year by year and this phenomenon has burdened the patient with extra charges. Consequently, this study will focus on designing an accurate implant via implementing the reverse engineering of three dimensional morphological study based on a particular population. By using the finite element analysis, this study will assist to predict the outcome and could become a useful tool for pre-clinical testing of newly designed implant. A prototype is then fabricated using 316L stainless steel by applying investment casting techniques which reduce manufacturing cost without jeopardizing implant quality. The finite element analysis showed the maximum von Mises stress was 66.88 MPa proximally with a safety factor of 2.39 against endosteal fracture, and micromotion was 4.73 μm which promotes osseointegration. This method offers a fabrication process of cementless femoral stems with lower cost, subsequently helping patients, particularly those from non developed countries.

scholarly journals Similar stress repartition for a standard uncemented collared femoral stem versus a shortened collared femoral stem

SICOT-J ◽  
2021 ◽  
Vol 7 ◽  
pp. 58
Author(s):  
Cécile Batailler ◽  
Jobe Shatrov ◽  
Axel Schmidt ◽  
Elvire Servien ◽  
Jean Marc Puch ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Femoral Stem ◽  
Short Stem ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Significant Difference ◽  
The Finite Element Analysis ◽  
Von Mises ◽  
Short Stems

Introduction: The design of uncemented femoral stems for use in total hip arthroplasty has evolved. Several uncemented short stems have been developed with different bone fixations, shapes, or stem lengths. The literature analyzing the biomechanical performance of short to standard stem lengths is limited. The aim was to compare the stress repartition on a standard uncemented stem and a shortened uncemented femoral stem with the same design features. Material and methods: This finite element analysis assessed the stress repartition on two femoral components with the same design (uncemented, collared, proximal trapezoidal cross-section, and a tapered quadrangular distal stem) but with two different lengths. The shortened stem was shorter by 40 mm compared to the standard stem. The stress repartition was analysed according to the Von Mises criterion. Results: The stress repartition was similar for the standard and shorter stem without significant difference (p = 0.94). The mean Von Mises stress was 58.1 MPa [0.2; 154.1] for the standard stem and 57.2 MPa [0.03; 160.2] for the short stem. The distal part of the standard stem, which was removed in the short stem, had mean stress of 3.7 MPa [0.2; 7.0]. Conclusion: The finite element analysis found similar stress repartitions between a standard uncemented collared stem and a short, collared stem with the same design. A clinical study assessing the clinical outcomes and the bone remodelling with a collared short stem would be interesting to confirm these first promising results.

Evaluation of Stiffness and Stress of External Fixators with Curved Acrylic Connecting Bars

2000 ◽  
Vol 13 (02) ◽  
pp. 65-72 ◽  
Author(s):  
R. Shahar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stainless Steel ◽  
Axial Compression ◽  
External Fixator ◽  
External Fixators ◽  
Analysis Method ◽  
Lateral Bending ◽  
Element Analysis ◽  
The Finite Element Analysis

SummaryThe use of acrylic connecting bars in external fixators has become widespread in veterinary orthopaedics. One of the main advantages of an acrylic connecting bar is the ability to contour it into a curved shape. This allows the surgeon to place the transcortical pins according to safety and convenience considerations, without being bound by the requirement of the standard stainless steel connecting bar, that all transcortical pins be in the same plane.The purpose of this study was to evaluate the stiffness of unilateral and bilateral medium-sized external fixator frames with different curvatures of acrylic connecting bars. Finite element analysis was used to model the various frames and obtain their stiffness under four types of load: Axial compression, four-point medio-lateral bending, fourpoint antero-posterior bending and torsion. The analysis also provided the maximal pin stresses occurring in each frame for each loading condition.Based on the results of this study, curvatures of acrylic connecting bars of up to a maximal angular difference between pins of 25° will result in very similar stiffness and maximal pin stresses to those of the equivalent, uniplanar stainless steel system. In both unilateral and bilateral systems the stiffness decreases slightly as angulation increases for axial compression and medio-lateral bending, increases slightly for torsion and increases substantially for antero-posterior bending.External fixator systems with curved acrylic connecting bars are commonly used in veterinary orthopaedics. This paper evaluates the biomechanical performance of such systems by applying the finite element analysis method. It shows that external fixators with curved acrylic connecting bars exhibit stiffness and maximal pin stresses which are similar to those of the standard stainless steel system.

scholarly journals Effects of Attraction of Vacuum Extractors of Different Materials and Pressures on the Fetal Head During Delivery

2021 ◽  
Author(s):  
Yu-Hsuan Chen ◽  
Kuo-Min Su ◽  
Ming-Tzu Tsai ◽  
Chi-Kung Lin ◽  
Cheng-Chang Chang ◽  
...  
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Von Mises Stress ◽  
Reactive Force ◽  
Fetal Head ◽  
Element Analysis ◽  
Vacuum Extractor ◽  
The Finite Element Analysis ◽  
Von Mises ◽  
Analysis Models

Abstract PurposeIn some cases where operative deliveries are required with vacuum extractor, and obstetricians could choose the vacuum extractor to facilitate the process smoother and safer. However, there is no related biomechanical literature about the influences of vacuum extractors fabricated from different materials and pressures of vacuum on the fetal head. Hence, we utilized the finite element method to investigate the influences of vacuum extractors manufactured from different materials on the fetal head under various extractive pressures.MethodsFirst, the finite element analysis models of vacuum extractor and fetal head were established. The vacuum extractor model was designed as a hemispherical shape and we compared silicone rubber and stainless steel for the materials of vacuum extractor. Subsequently, four different vacuum pressures were applied as the factors for investigation—500-cm H2O, 600-cm H2O, 700-cm H2O, and 800-cm H2O. Finally, we observed and analyzed the reactive force on the fetal head, von Mises stress of vacuum extractor, and von Mises stress on the skull of fetal head to evaluate the influences of vacuum extractors of different materials under different pressures. ResultsThe results demonstrated that different vacuum pressures had only a slight difference of influences on the fetal head. The use of stainless-steel vacuum extractors caused a relatively larger reactive force (358.04–361.37 N) and stress (13.547–13.675 MPa) on the fetal head. ConclusionsNon-metallic or relatively softer materials could be selected when using a vacuum extractor for operative delivery to avoid complications such as scalp scratch, and even cephalohematoma and intracerebral hemorrhage.

Effect of Process Parameters on Temperature Field during Laser Sintering of 316L Stainless Steel Powder

2013 ◽  
Vol 668 ◽  
pp. 844-849 ◽  
Author(s):  
Nai Fei Ren ◽  
Dian Wang ◽  
Lei Jia ◽  
Xiao Bing Ge
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stainless Steel ◽  
Temperature Field ◽  
316L Stainless Steel ◽  
Steel Powder ◽  
Scanning Speed ◽  
Laser Sintering ◽  
Stainless Steel Powder ◽  
Element Analysis

Finite element analysis software ANSYS is a platform, Using the Parametric Design Language of APDL language to write programs to simulate the temperature field of the laser sintering of 316L stainless steel powder. Building the model of Finite element analysis to analysis the simulation's various difficulties, such as the thermal parameters at different temperatures, the loading of the heat flux and some of the key parameters. Researching the affect of laser power and scanning speed on the temperature field, it’s valuable in researching the temperature field of the metal powder sintering

scholarly journals Stress Distribution Analysis of the Rectangular and Star-Blade for Plastic Crusher Machine Using Finite Element Analysis

2021 ◽  
Vol 2111 (1) ◽  
pp. 012015
Author(s):  
Nalendro Mataram ◽  
Sigiet Haryo Pranoto ◽  
Rizqi Ilmal Yaqin ◽  
Anis Siti Nurrohkayati ◽  
Noer Aden Bahry ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plastic Waste ◽  
Von Mises Stress ◽  
Distribution Analysis ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Stress Result ◽  
Von Mises ◽  
Better Than

Abstract Recycling plastic waste can help reduce plastic waste, which is the world’s largest problem. The first solution is a plastic crusher machine, which converts plastic packaging into pellets, especially for plastics made from polyester, which is often used in bottle packaging. An integral part of the crushing machine is the crushing blade, which determines the design and analysis of the blade. The finite element analysis method is widely used in engineering analysis. Its results can provide useful information for the analysis of manufacturing processes. A rectangular blade and a star-shaped blade are the two types to consider. The analytical results obtained on the blade of the crusher machine in the rectangular shape that was given loads by 200 N, 400 N, and 600 N are 1.285 × 103 N/m2, 2.570 × 103 N/m2, and 3.855 × 103 N/m2, respectively. We obtained the displacements are 1.080 × 10-6 mm, 2.160 × 10-6 mm, and 3.241 × 10-6 mm, respectively. The maximum von mises stress result on consecutive star-shaped blades are 8.890 × 102 N/m2, 1.778 × 103 N/m2, and 2.667 × 103 N/m2. The displacement obtained are 1.211 × 10-6 mm, 2.422 × 10-6 mm, and 3.633 × 10-6 mm. The results of this analysis indicate that for the star blade, the shape is better than for the rectangular blade at the same time, and for the star blade, the stress is smaller than for the rectangular blade. Based on this simulation, the safety factor is 15, which means that it is more than 1, which means that it is safe.

On the Effect of Screw Preload on the Stress Distribution of Mandibles During Segmental Defect Treatment Using an Additively Manufactured Hardware

2016 ◽  
Author(s):  
Amirhesam Amerinatanzi ◽  
Narges Shayesteh Moghaddam ◽  
Ahmadreza Jahadakbar ◽  
David Dean ◽  
Mohammad Elahinia
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Fixation Device ◽  
Element Analysis ◽  
Porous Niti ◽  
The Finite Element Analysis ◽  
Low Stiffness ◽  
Von Mises

The most common method for mandibular reconstructive surgery is the use of a Ti-6Al-4V fixation device and a fibular double barrel graft. This highly stiff fixation hardware (E = 112 GPa) often shields the bone graft (E = 20 GPa) from carrying the load, which may result in bone resorption. Highly stiff Ti-6Al-4V fixation hardware is also likely to concentrate stress in the fixation plate or at screw threads, possibly leading to hardware cracking or screw pull-out. As a solution for that, we have proposed and studied the effect of using a low stiffness, porous NiTi fixation device [1–4]. Although the stress in the fixation device is increased, using such low stiffness fixation hardware, is preferable to have an even higher stress on the graft in order to minimize the risk of resorption or hardware failure. We assume that preloading screws allows them to better engage the fixation hardware with the plate and the surrounding bone and causes an increased von Mises stress. The fixation device can be patient-specific and additively manufactured, such that the shape would match the outer surface of the cortical bone. In this study, we modeled a healthy cadaver mandible via CT-derived 3D surface data. The mandible was virtually resected in the molar region (M1−3). The model simulated the result of reconstructive surgery under the highest chewing loading regime (i.e., 526 N on first right molar tooth [5, 6]) where reconstruction was done with either Ti-6Al-4V fixation hardware or patient specific, stiffness-matched, porous NiTi fixation hardware. The calibration of the material properties for this simulation was done using experimentally obtained data (DSC and compression tests) of Ni-rich NiTi bulk samples. The analyzed term in the finite element analysis was stress distribution in the cortical and cancellous bone. Porous NiTi fixation devices were also produced using Selective Laser Melting (SLM) using the geometry of the aforementioned cadaver mandible. In this paper we have studied the effect of additional torque or preload on the performance of the fixation plates. The finite element analysis demonstrated that applying a preload to the screws increased the stress on the bone. Under similar levels of applied preload, the porous NiTi fixation device showed an increased level of von Mises stress in the bone, particularly in the graft. Additionally, the analysis indicated the higher level of stress on the bone surrounding the screws for the case of using NiTi, which could contribute to increasing screw stability. The fabricated patient-specific fixation hardware not only matched the shape of cortical bone but also contained the level of porosity that defines the appropriate modulus of elasticity.

FINITE ELEMENT ANALYSIS OF TOTAL KNEE REPLACEMENT WITH VARIOUS MISALIGNMENT ANGLES IN THE SAGITTAL PLANE

2016 ◽  
Vol 16 (07) ◽  
pp. 1650096 ◽  
Author(s):  
XIAOQIANG PANG ◽  
LING WANG ◽  
ZHEN WANG ◽  
LEI GENG ◽  
DICHEN LI ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Tibial Component ◽  
Sagittal Plane ◽  
Knee Prosthesis ◽  
Femoral Stem ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Custom Made

Custom-made prosthetic replacement is a common method of limb reconstruction after surgery of bone tumors. A custom-made tumor knee prosthesis was retrieved after fracture of the tibial stem. The fracture of stem was considered to be associated with some misalignment between the axis of femur and that of the femoral stem, which might cause stress concentration within the tibial component and eventually lead to fracture. To verify this hypothesis, finite element analysis was carried out to study the effect of various tilting degree (6[Formula: see text] forward, 0[Formula: see text] and 6[Formula: see text] backward) of the stem in the sagittal plane on the stress distribution within the tibial component. The calculated maximum Von Mises stress in the tibial component was 225.8, 362.8 and 511.3[Formula: see text]MPa when the femoral component was tilted for 6[Formula: see text] forward, [Formula: see text] and [Formula: see text] backward, respectively. The results demonstrated that the misalignment of femoral components in the sagittal plane has marked effect on the stress distribution of the tibial component.

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