Axial Torsion Research Articles

Feasibility of 3D-Printed Locking Compression Plates with Polyether Ether Ketone (PEEK) in Tibial Comminuted Diaphyseal Fractures.

The applicability of a polyether ether ketone locking compression plate (PEEK LCP) fabricated using FDM (fused deposition modeling)-based 3D printing to treat actual patients was studied. Three different tests-bending, axial compression, and axial torsion-were conducted on tibial non-osteoporotic comminuted diaphyseal fracture samples fixed with the commercial titanium alloy LCP and 3D-printed PEEK LCP. Comparing the outcomes of these tests revealed that the commercial titanium alloy LCP underwent plastic deformation in the bending and axial torsion tests, though the LCP did not fail even when an external force greater than the maximum allowable load of the tibia fixture of the LCP was applied. Elastic deformation occurred in the 3D-printed PEEK LCP in the bending and axial torsion tests. However, deformation occurred even under a small external force, and its stiffness was 10% compared to commercial titanium alloy LCP. Thus, 3D-printed PEEK LCP can be applied to the fracture conditions in non-weight-bearing regions. The experimental results reveal detailed insights into the treatment of actual patients by considering the stiffness and high toughness of 3D-printed PEEK LCP.

Unexpected bending behavior of architected 2D lattice materials.

Architected two-dimensional (2D) lattice materials consisting of elastic beams are appealing because of their tunable sign of Poisson's ratio. A common belief is that such materials with positive and negative Poisson's ratios display anticlastic and synclastic curvatures, respectively, when bent in one direction. Here, we show theoretically and demonstrate experimentally that this is not true. For 2D lattices with star-shaped unit cells, we find a transition between anticlastic and synclastic bending curvatures controlled by the beam's cross-sectional aspect ratio even at a fixed Poisson's ratio. The mechanisms lay in the competitive interaction between axial torsion and out-of-plane bending of the beams and can be well captured by a Cosserat continuum model. Our result may provide unprecedented insights to the design of 2D lattice systems for shape-shifting applications.

Stochastic analysis of semi-rigid steel frames using a refined plastic-hinge model and Latin hypercube sampling

This paper proposes a stochastic analysis model that combines the refined plastic-hinge analysis method with the Monte Carlo simulation to predict the realistic resistance of steel structures. The model treats the uncertainty quantifications of the material properties, geometry, and semi-rigid connections as independent random variables in the discretized stochastic fields using Latin hypercube sampling. The critical resistance of the structures in each simulation is determined using the general displacement control method and advanced analysis algorithms. The statistical approach is employed to compute the mean values and the standard deviation of the load-carrying capacity of the steel frames. The study finds that the uncertainties in material properties are the most sensitive, and the correlation of these parameters with the strength of structures is also significant. To improve the load and resistance factor design criterion, a resistance factor of 0.93 is suggested for the beam-columns in the frames under axial force, torsion, and biaxial bending moments. A stochastic response spectrum is proposed to define the boundary of strength, where a clearly defined plastic mechanism is attained. Furthermore, this study provides valuable insights into the stochastic resistance of steel frames, which are essential for practical engineering applications.

On the Role of Torsion and Higher Forms in Off‐Shell Supergravity

AbstractThe presence of a nonvanishing totally antisymmetric (super)torsion, equivalent to an axial vector, and higher forms in the “new minimal” and “old minimal” off‐shell formulations of , supergravity is elaborated. The geometric superspace approach and study both the geometric Lagrangian and the off‐shell closure of the Bianchi identities in this framework, showing how the aforementioned axial vector torsion contributes to both the new and the old minimal set of auxiliary fields is adopted. In particular, to reproduce (a variant of) the old minimal set within the geometric setup, two real auxiliary 3‐form potentials.

CLOSED BKS-TYPE UNIVERSES AND DIRAC SPIN EFFECT IN THE RAINBOW GRAVITY

The result related to astrophysical datasets suggest that our universe has recently entered a phase of accelerated expansion. This accelerated expansion is not a situation predicted by the general theory of relativity. Therefore, the emergence of alternative approaches to general relativity has become inevitable. Modifying general relativity and absolute parallelism theory are just two of these theories. In addition, with the discovery of gravitational waves, the need for a view that includes gravitational quantum contributions arose. In this context, rainbow gravity has an approach that also offers quantum contributions to the theory of general relativity and absolute parallelism. In this study, axial vector torsion is calculated for BKS-type universe models using the rainbow gravity formalism. With the calculations made, the vector part and axial vector part components of the torsion tensor are obtained. The spin process, which contributes to the Dirac particles, is also investigated using the rainbow gravitational theory. However, since the obtained axial vector fragment is in time-like form, it is concluded that the spin vector of the Dirac particle is constant. The axial part of the torsion tensor for general BKS-type universe models is calculated and presented in a table for some well-known rainbow functions.

An Immunological and Biomechanical Comparison of PEEK-Zeolite and PEEK Interbody Fusion Devices.

A laboratory study comparing PEEK-zeolite and PEEK spinal implants in an ovine model. This study challenges a conventional spinal implant material, PEEK, to PEEK-zeolite using a non-plated cervical ovine model. Although widely used for spinal implants due to its material properties, polyether ether ketone (PEEK) is hydrophobic, resulting in poor osseointegration, and elicits a mild non-specific foreign body response. Zeolites are negatively-charged aluminosilicate materials that are hypothesized to reduce this pro-inflammatory response when used as a compounding material with PEEK. Fourteen skeletally mature sheep were each implanted with one PEEK-zeolite interbody device and one PEEK interbody device. Both devices were packed with autograft and allograft material and randomly assigned to one of two cervical disc levels. The study involved two survival timepoints (12 and 26wk) and biomechanical, radiographic, and immunological endpoints. One sheep expired from complications not related to the device or procedure. Biomechanical evaluation was based on measures of segmental flexibility, using a six-degrees-of-freedom pneumatic spine tester. Radiographic evaluation was performed using microCT scans in a blinded manner by three physicians. Levels of the pro-inflammatory cytokines interleukin-1β, interleukin-6, and tumor necrosis factor alpha at the implant were quantified using immunohistochemistry. PEEK-zeolite and PEEK exhibited equivalent range of motion in flexion extension, lateral bending and axial torsion. Motion was significant reduced for implanted devices at both time points as compared to native segments. Radiographic assessments of fusion and bone formation were similar for both devices. PEEK-zeolite exhibited lower levels of interleukin-1β (P=0.0003) and interleukin-6 (P=0.0300). PEEK-zeolite interbody fusion devices provide initial fixation substantially equivalent to PEEK implants but exhibit a reduced pro-inflammatory response. PEEK-zeolite devices may reduce the chronic inflammation and fibrosis previously observed with PEEK devices.

Design and Stress Analysis of Wider Lateral Lumbar Interbody Fusion (LLIF) Cages: A Finite Element Study

It is important to better understand the impact of intervertebral cage material and design on the stress distribution in vertebral bodies to aid eliminate complications like subsidence and improve performance after lumbar interbody fusion. In this study, the cage materials of PLA, PEEK, titanium, and stainless steel were compared using a finite element model of the L3-L4 motion segment. Strain and stress were measured in the vertebra and cage when the model was loaded in axial compression, flexion, and torsion. Additionally, a wider cage designed to conform to the vertebral endplates could potentially evenly distribute and reduce the overall stress at the endplates. The wider cages increased the area in contact with the bone, distributing the stress more evenly and providing a potential way to decrease the danger of subsidence. Such cages could be manufactured by additive manufacturing.

Is the construct stability of the acetabular cup affected by the acetabular screw configuration in bone defect models?

BackgroundIn revision surgery with significant segmental acetabular defects, adequate implant selection and fixation methods are critical in determining successful bony ingrowth. Commercially available total hip prosthesis manufacturers generally offer additional multi-hole options of acetabular shells with identical designs for use in revision THAs where screw holes configurations vary from product to product. This study aims to compare the mechanical stability of the two types of acetabular screw constructs for the fixation of acetabular components: spread-out and pelvic brim-focused configurations.MethodsWe prepared 40 synthetic bone models of the male pelvis. In half of the samples with acetabular defects, identical curvilinear bone defects were manually created using an oscillating electrical saw. On the right side, multi-hole-cups in which the direction of the screw holes are centered on the pelvic brim (brim-focused) and, on the left side, multi-hole-cups with the direction of the screw hole spread throughout the acetabulum (spread-out) were implanted into the pelvic synthetic bones. Coronal lever-out and axial torsion tests were performed with a testing machine, measuring load versus displacement.ResultsThe average torsional strengths were significantly higher in the spread-out group over the brim-focused group regardless of the presence of the segmental defect of the acetabulum (p < 0.001). But for the lever-out strength, the spread-out group exhibited significantly higher average strength over the brim-focused group for the intact acetabulum (p = 0.004), whereas the results were reversed in the brim-focused group when the defects were generated (p < 0.001). The presence of acetabular defects reduced the average torsional strengths of the two groups by 68.66% versus 70.86%. In comparison, the decrease in the average lever-out strength was less significant for the brim-focused group than the spread-out group (19.87% vs. 34.25%) (p < 0.001).ConclusionConstructs of multi-hole acetabular cups with the spread-out screw holes configuration exhibited statistically better axial torsional strength and coronal lever-out strength. With the presence of posterior segmental bone defects, the spread-out constructs demonstrated significantly better tolerance to axial torsional strength. Still, they exhibited inverted results of higher lever-out strength in the pelvic brim-focused constructs.

Breed and loading history influence in vivo skeletal strain patterns in pre-pubertal female chickens

The influence of loading history on in vivo strains within a given specie remains poorly understood, and although in vivo strains have been measured at the hindlimb bones of various species, strains engendered during modes of activity other than locomotion are lacking, particularly in non-human species. For commercial egg-laying chickens specifically, there is an interest in understanding their bones' mechanical behaviour, particularly during youth, to develop early interventions to prevent the high incidence of osteoporosis in this population. We measured in vivo mechanical strains at the tibiotarsus midshaft during steady activities (ground, uphill, downhill locomotion) and non-steady activities (perching, jumping, aerial transition landing) in 48 pre-pubescent female (egg-laying) chickens from two breeds that were reared in three different housing systems, allowing varying amounts and types of physical activity. Mechanical strain patterns differed between breeds, and were dependent on the activity performed. Mechanical strains were also affected by rearing environment: chickens that were restricted from performing dynamic load bearing activity due to caged-housing generally exhibited higher mechanical strain levels during steady, but not non-steady activities, compared to chickens with prior dynamic load-bearing activity experience. Among chickens with prior experience of dynamic load bearing activity, those reared in housing systems that allowed more frequent physical activity did not exhibit lower mechanical strains. In all groups, the tibiotarsus was subjected to a loading environment consisting of a combination of axial compression, bending, and torsion, with torsion being the predominant source of strain. Aerial transition landing produced the highest strain levels with unusual strain patterns compared to other activities, suggesting it may produce the strongest anabolic response. These results exemplify how different breeds within a given specie adapt to maintain different patterns of mechanical strains, and how benefits of physical activity in terms of resistance to strain are activity-type dependent and do not necessarily increase with increased physical activity. These findings directly inform controlled loading experiments aimed at studying the bone mechanoresponse in young female chickens and can also be associated to measures of bone morphology and material properties to understand how these features influence bone mechanical properties in vivo.

Structural behaviour of an asymptotic curtain wall stiffened with lamella couplings

Asymptotic structures are a novel construction system that allows fabrication from straight and flat lamellas, that are bent and twisted into the design shape. The challenge of this strategy is to design sufficiently slender profiles for deformation while maintaining structural stability in the curved state. This paper investigates a strategy to reinforce two parallel lamella members through timber couplings to improve their structural performance. The structural behaviour of the reinforced structure is investigated experimentally and numerically, and compared to the original design. The structural principle of coupling reinforcement is investigated for a double-lamella member under axial force, shear force, bending moment, and torsion. Results show that the structural stiffness and the load-bearing capacity of the asymptotic curtain wall under point load and wind load increase significantly if coupled. This effect can further be improved, by increasing the material stiffness, parallel offset, and the number of coupling blocks. Moreover, using a continuous coupling between the two lamellas to form a steel-timber-steel sandwich member can stiffen the asymptotic curtain wall structure by 436% under wind load, in comparison with 76% using two discrete timber couplings for each member.

The uncommon complications of Meckel's diverticulum: A single center case series study and literature review

Introduction and importanceMeckel's diverticulum is the most common congenital true diverticula of the gastrointestinal tract with 4–9% life time risk of complications. It is difficult to diagnose preoperatively other than having high index of suspicion. Therefore, the aim of this case series is to present the rare presentation of this disease and create awareness for clinician to deliver early intervention so that associated mortality and morbidity will be minimized. Case presentationHere we present four cases of Meckel's diverticulum managed in single center during a period of one year. Two cases were presented as isolated gangrenous Meckel's diverticulum with small bowel obstruction. The remaining two were: an adult male patient operated for generalized peritonitis as a result of perforated Meckel's diverticulitis and a child with intussusception in which Meckel's diverticulum was secondarily obstructed. Clinical discussionThe less frequent complications of Meckel's diverticulum are more challenging to diagnose. It carries higher rate of morbidities since early diagnosis is difficult; especially, isolated axial torsion of the Meckel's diverticulum that we are presenting in this case series. Therefore it is prudent to consider for a pain originating from central abdomen which gets diffuse in the meantime unlike symptoms of complicated appendicitis as symptomatic Meckel's diverticulum. ConclusionThe rare complications of Meckel's diverticulum need high index of suspicion to diagnose as their symptoms mimic other pathologies which cause diffuse abdominal pain. Timely intervention can prevent hospital mortality, morbidity and decrease duration of hospital stay.

Cyclic behavior and ultimate bearing capacity of circular concrete-filled double skin steel tube members subjected to combined compression and torsion

This paper presents a pseudo-static test investigation and finite element analysis on the behavior of circular concrete-filled double skin steel tube (CFDST) members under axial compression and torsion. The hollow ratio (χ) and axial compression ratio (n) are considered in the test study. The ductility, hysteretic behavior, failure modes, and compression–torsion correlation of circular CFDST members are discussed. The comparison results show that the validated finite element model is capable to capture the behavior of circular CFDST members under compression and torsion. The effect of loading paths and various parameters on the compression–torsion correlation of circular CFDST members are analyzed. Parametric analyses are carried out to investigate the effect of key parameters, such as material properties, nominal steel ratio, the wall thickness of inner steel tube, and hollow ratio on the compression–torsion correlation of circular CFDST members. It can be seen that the circular CFDST members under compression and torsion possess good load-bearing capacity, energy dissipation, and ductility properties. The loading paths, yield strength of inner and outer steel tubes, nominal steel ratio, and the wall thickness of inner steel tubes have little effect on the compression–torsion correlation of the composite members. When the axial compression ratio is less than 0.2, the axial compression load can slightly improve the torque capacity of circular CFDST members. Finally, the compression–torsion correlation equation of these members was proposed by regression analysis, and design formulas with good accuracy for predicting the torque capacity of circular CFDST members under compression and torsion were proposed.

Biomechanical comparison of canine femurs implanted with either cemented (CFX®) or cementless (with lateral bolt) (BFX®+lb) total hip replacement under 4-point bending or torsional loads.

Objective: Compare biomechanical properties of femurs implanted with either BioMedtrix™ biological fixation with interlocking lateral bolt (BFX®+lb) or cemented (CFX®) stems when subjected to 4-point bending or axial torsional forces. Study Design: Twelve pairs of normal medium to large cadaveric canine femora were implanted with a BFX + lb (n = 12) and a CFX (n = 12) stem-one in the right and one in the left femora of the pair. Pre- and post-operative radiographs were made. Femora were tested to failure in either 4-point bending (n = 6 pairs) or axial torsion (n = 6 pairs), and stiffness, load or torque at failure, linear or angular displacement, and fracture configuration were noted. Results: Implant position was acceptable in all included femora, but CFX stems were placed in less anteversion than BFX + lb stems in the 4-point bending group (median (range) 5.8 (-1.9-16.3) vs. 15.9 (8.4-27.9) anteversion, respectively (p = 0.04)). CFX implanted femora were more stiff than BFX + lb implanted femora in axial torsion (median (range) 2,387 (1,659-3,068) vs. 1,192 (795-2,150) N*mm/o, respectively (p = 0.03)). One of each stem type, from different pairs, did not fail in axial torsion. There was no difference in stiffness or load to failure in 4-point bending, or in fracture configuration for either test, between implant groups. Conclusion: Increased stiffness of CFX implanted femurs under axial torsional forces may not be clinically relevant as both groups withstood expected in vivo forces. Based on this acute post-operative model using isolated forces, BFX + lb stems may be a suitable replacement for CFX stems in femurs with normal morphology (stovepipe and champagne flute morphology were not tested).

Natural Frequency and Modes of the Longitudinal and Torsional Vibrations in the Bars with Variable Cross Section

The paper is focused on the problem of natural frequencies and modes determination based on perturbation theory for longitudinal and torsional vibrations in bars with variable cross section. The mechanical properties and cross section geometry of the bar are changing small from the average value with regard to longitudinal coordinate. Based on the theory of small perturbations the analytical solution is obtained for natural frequencies and modes of the stationary harmonic vibrations in bars. The efficiency of the proposed method is supported by comparison and good agreement of the obtain results with a sharp solution for a given cross section profiles. It was established that the approximate solution is working good up to the ratio 2.5–3 between maximum and minimum diameter of cross section. The results of numerical simulations are aimed to estimate the geometry and elastic behavior of the metallic specimens for very high cycle fatigue experimental investigation under axial tension-compression and torsion loadings. The piezoelectric fatigue testing system and procedure is based on stationary vibration excitation in the metallic specimen at the first mode natural frequency.

Geometric variation of the human tibia-fibula: a public dataset of tibia-fibula surface meshes and statistical shape model.

Variation in tibia geometry is a risk factor for tibial stress fractures. Geometric variability in bones is often quantified using statistical shape modelling. Statistical shape models (SSM) offer a method to assess three-dimensional variation of structures and identify the source of variation. Although SSM have been used widely to assess long bones, there is limited open-source datasets of this kind. Overall, the creation of SSM can be an expensive process, that requires advanced skills. A publicly available tibia shape model would be beneficial as it enables researchers to improve skills. Further, it could benefit health, sport and medicine with the potential to assess geometries suitable for medical equipment, and aid in clinical diagnosis. This study aimed to: (i) quantify tibial geometry using a SSM; and (ii) provide the SSM and associated code as an open-source dataset. Lower limb computed tomography (CT) scans from the right tibia-fibula of 30 cadavers (male n = 20, female n = 10) were obtained from the New Mexico Decedent Image Database. Tibias were segmented and reconstructed into both cortical and trabecular sections. Fibulas were segmented as a singular surface. The segmented bones were used to develop three SSM of the: (i) tibia; (ii) tibia-fibula; and (iii) cortical-trabecular. Principal component analysis was applied to obtain the three SSM, with the principal components that explained 95% of geometric variation retained. Overall size was the main source of variation in all three models accounting for 90.31%, 84.24% and 85.06%. Other sources of geometric variation in the tibia surface models included overall and midshaft thickness; prominence and size of the condyle plateau, tibial tuberosity, and anterior crest; and axial torsion of the tibial shaft. Further variations in the tibia-fibula model included midshaft thickness of the fibula; fibula head position relative to the tibia; tibia and fibula anterior-posterior curvature; fibula posterior curvature; tibia plateau rotation; and interosseous width. The main sources of variation in the cortical-trabecular model other than general size included variation in the medulla cavity diameter; cortical thickness; anterior-posterior shaft curvature; and the volume of trabecular bone in the proximal and distal ends of the bone. Variations that could increase the risk of tibial stress injury were observed, these included general tibial thickness, midshaft thickness, tibial length and medulla cavity diameter (indicative of cortical thickness). Further research is needed to better understand the effect of these tibial-fibula shape characteristics on tibial stress and injury risk. This SSM, the associated code, and three use examples for the SSM have been provided in an open-source dataset. The developed tibial surface models and statistical shape model will be made available for use at: https://simtk.org/projects/ssm_tibia.

Statistical shape modelling reveals differences in hamstring morphology between professional rugby players and sprinters

ABSTRACT Hamstring morphology may play an important role in understanding the aetiology of hamstring injury. Currently, the methods available to capture detailed morphological data such as muscle shape have not been utilized for the hamstring muscles. The aim of this study was to examine the utility of statistical shape modelling (SSM) for describing and comparing hamstring muscle shape in rugby and sprinting athletes. Magnetic resonance images of both thighs of nine elite male rugby players and nine track and field sprinters were analysed. Images were converted to three-dimensional models enabling generation of four statistical shape models. Principal components describing the shape variation in the cohort were derived and evaluated. Six principal components were sufficient to discriminate differences in the shape of the hamstring muscles of rugby and sprinting athletes with 89% classification accuracy. Distinct shape features distinguishing rugby players from sprinters included size, curvature and axial torsion. These data demonstrate that SSM is useful for understanding hamstring muscle shape and that meaningful variation can be identified within a small sample. This method can be used in future research to enhance the anatomical specificity of musculoskeletal modelling and to understand the relationship between hamstring shape and injury.

Search for Manifestations of Spin–Torsion Coupling

We investigate the axial vector spin–torsion coupling effects in the framework of the Poincaré gauge theory of gravity with the general Yang–Mills type Lagrangian. The dynamical equations for the “electric” and “magnetic” components of the torsion field variable are obtained in the general form and it is shown that the helicity density and the spin density of the electromagnetic field appear as the physical sources. The modified Maxwell’s equations for the electromagnetic field are derived, and the electromagnetic wave propagation under the action of the uniform homogeneous torsion field is considered. We demonstrate the Faraday effect of rotation of the polarization for such a wave and establish the strong bound on the possible cosmic axial torsion field from the astrophysical data.

Performance of recycled aggregate concrete-filled high-strength steel tubes under axial compression, tension and torsion

This paper reports the performance of recycled aggregate concrete-filled high-strength steel tubes (RAC-FHST) under axial compression, tension and torsion. A total of 50 specimens, including 22 compressive specimens, 16 tensile ones and 12 torsional ones, were tested. The main parameters varied in the tests were the sectional type, the steel yield strength and the replacement ratio of recycled coarse aggregate (RCA). Analysis on the full-range load–deformation response, the typical failure modes, the ultimate strength, the passive confinement effect and the influence of key parameters were conducted. Results reveal that the use of RCA affected the failure modes especially when subjected to tension or torsion. Meanwhile, the performance of RAC-FHST is improved due to the excellent confinement effect of high-strength steel tube. The finite element modelling method was used to investigate the mechanical property and the effects of important parameters. Simplified models for the calculation of ultimate compressive, tensile and torsional strengths of RAC-FHST were proposed. Based on reliability analysis, the effects of the steel yield strength, the concrete strength and the confinement factor on the reliability index of RAC-FHST were evaluated.

Canceling Notch Improves the Mechanical Safety of Clavicle Locking Plate: A 3D Finite Element Study.

Implant failure is a disastrous complication of the operative treatment of midshaft clavicle fractures, and improving the osteosynthesis plate is a strategy for preventing this. We aimed to investigate whether canceling the notch and adding screw-hole inserts enhanced the mechanical properties of the plate. A clavicle model was generated based on the CT images of six adult volunteers (age range, 20-40 years; three males and three females; height range 160-175) using dedicated software, and a midshaft fracture model was created. The domestically made seven-hole locking plate commonly used for midshaft clavicle fractures was simulated (Model I); modifications were made to the plate (Model II). Using 3D finite element analysis, we simulated the fracture construct under three different load conditions-downward cantilever bending, axial compression, and axial torsion-and compared the stress distribution. We found that under axial compression, Model II experienced its maximum stress on the plate at 551.9MPa, which was less than that in Model I (790.4 MPa). Moreover, a greater stress concentration at the fracture site was observed under axial torsion, despite the maximum stress of both the models being similar. Canceling the notch and filling the screw holes near the fracture can ameliorate stress concentration on the internal fixation construct and enhance its reliability under axial compression. This improvement has substantial effects on the mechanical properties of implants and potentially prevents implant failure. Modern osteosynthesis anatomical implants need to be improved.

Cortical bone continuum damage mechanics constitutive model with stress triaxiality criterion to predict fracture initiation and pattern.

A primary objective of finite element human body models (HBMs) is to predict response and injury risk in impact scenarios, including cortical bone fracture initiation, fracture pattern, and the potential to simulate post-fracture injury to underlying soft tissues. Current HBMs have been challenged to predict the onset of failure and bone fracture patterns owing to the use of simplified failure criteria. In the present study, a continuum damage mechanics (CDM) model, incorporating observed mechanical response (orthotropy, asymmetry, damage), was coupled to a novel phenomenological effective strain fracture criterion based on stress triaxiality and investigated to predict cortical bone response under different modes of loading. Three loading cases were assessed: a coupon level notched shear test, whole bone femur three-point bending, and whole bone femur axial torsion. The proposed material model and fracture criterion were able to predict both the fracture initiation and location, and the fracture pattern for whole bone and specimen level tests, within the variability of the reported experiments. There was a dependence of fracture threshold on finite element mesh size, where higher mesh density produced similar but more refined fracture patterns compared to coarser meshes. Importantly, the model was functional, accurate, and numerically stable even for relatively coarse mesh sizes used in contemporary HBMs. The proposed model and novel fracture criterion enable prediction of fracture initiation and resulting fracture pattern in cortical bone such that post-fracture response can be investigated in HBMs.