Biaxial Loading Research Articles

Dynamic responses of radiation-induced heavyweight concrete subjected to biaxial compression

As a good shielding material, heavyweight concrete is largely utilized for building the Concrete Biological Shielding (CBS) wall of the commercial nuclear power plant, and is often subjected to the biaxial loadings with a strain rate possibly varying from 10−5s−1 to 10−2s−1. This paper assesses the combined effects of the lateral stress and the strain rate on the compressive strength of radiation-induced heavyweight concrete on the example of serpentine concrete. For this goal, a 3-dimensional rectangular numerical concrete specimen containing special aggregates and ITZs was firstly established. Exposed to neutrons of different fluences, the initial damages caused by the fast neutron were assessed by a thermal-mechanical approach. Then, a series of static and dynamic biaxial compressive tests on the rectangular specimens having initial damages of different degrees were carried out by finite element analysis via ABAQUS. The failure modes, the crack patterns, and the ultimate compressive strengths of the pre-irradiated serpentine concrete were obtained numerically. Finally, based on the numerical results and the classical "Kupfer-Gerstle" ("K-G") criterion, this paper derives the biaxial strength criterion of the radiation-induced heavyweight concrete undergoing both lateral stress and strain rate. Through the formula, it was found that the fast neutron fluence of high level reduces significantly the biaxial compressive strength of the heavyweight concrete. Besides, if the heavyweight concrete undergoes additionally lateral stress and the strain rate, the biaxial compressive strength could be enhanced. The enhancement effect was maximized at the lateral stress ratio of 0.5 and the strain rate of 10−2s−1. The current numerical approach was developed with a potential application to the lifetime extension of the heavyweight concrete infrastructures used in commercial nuclear reactors.

Experimental studies of the influence of biaxial bending on the crack resistance of reactor pressure vessel steel

Background: to assess the residual life of nuclear reactor hulls in Ukraine, normative temperature dependences of the crack resistance of hull steels obtained on standard samples with a deep through crack under plane strain conditions are used. However, it is known that the thickness of the wall of the reactor body is subject to biaxial loading, which affects the value of the crack resistance characteristics. Therefore, in order to substantiate the possibility of lengthening beyond the design resource of VVER-1000 reactor hulls, an experimental study of the effect of biaxial load on the crack resistance characteristics of hull reactor steel 15X2NMFAA is relevant. Objective: development of an experimental technique and investigation of crack resistance under biaxial loading on small-sized samples in the the brittle-ductile transition temperature range of reactor steels. Methods: on the basis of numerical and engineering calculations, a specimen was developed, the corresponding additional equipment for its tests under biaxial loading on a uniaxial servo-hydraulic machine. The influence of biaxial bending on the fracture toughness of reactor steel 15X2NMFAA was experimentally investigated. Results: the results obtained on cruciform specimen are calculated according to the ASTM 1921 standard and plotted on the Master curve (temperature dependence of fracture toughness). The analysis showed that the data on crack resistance obtained on samples with "short" (a/W=0.1...0.2) linear and surface semi-elliptical cracks exceed the upper limit of the confidence interval of the Master curve, and biaxial loading of cruciform specimen reduces crack resistance compared to uniaxial loading.

Numerical analytical method of predicting the durability of fibrous composite materials under conditions of biaxial cyclic loading

A combined numerical-analytical method for predicting the durability of fibrous composite materials under conditions of biaxial cyclic loading is proposed. The model of nonlinear elastic behavior of random composites is used. The mechanics problem of determining the stress-strain state in the matrix and fibers is solved within the framework of the physically nonlinear theory of elasticity with the use of numerical methods. To predict the durability of an anisotropic composite in the macro volume, the matrices strengthening effect were used. The method of determining the equivalent stress used for asymmetric two-dimensional loading is considered. The influence of the average stress on the fatigue characteristics of the matrix with nonlinear strengthening is shown. Examples are given that illustrate the importance of the mutual influence of nonlinear elastic and anisotropic properties of the composite on the redistribution of stresses in the fibers and the matrix. As a practical result, we can note the possibility of predicting the long-term strength of the material when the field of cyclic stresses is determined in the vicinity of the inclusions. For a detailed analysis of local stress fields and specification of the type of complex load in structural elements, a numerical analysis was performed using finite element programs for a single, forming cell in the context of random homogenization.

Coupled versus energetic nonlocal failure criteria: A case study on the crack onset from circular holes under biaxial loadings

The phenomenon of brittle crack onset stemming from a circular hole in an infinite plate subjected to remote biaxial loading is herein investigated. A thorough analysis on the influence of the loading biaxiality reveals the existence of a wide casuistry in the sign and trend distributions of the stress field and Stress Intensity Factor, thus rendering it an exhaustive case study for assessing different failure criteria. Subsequently, three different approaches are used to determine the biaxial safety domains, two of which rely on the coupling of stress and energy conditions for failure, namely Finite Fracture Mechanics and Cohesive Zone Model, plus the purely energy-driven Phase Field model of fracture. Noteworthy, Finite Fracture Mechanics predicts the existence of a region in the loading space where failure is exclusively governed by the energy condition. Likewise, it is mathematically proven that the system of equations governing Dugdale's Cohesive Zone Model is equivalent to the first-order minimization condition of the energy balance, the resultant predictions being fairly close to those obtained by Finite Fracture Mechanics. Lastly, the Phase Field model of fracture is numerically implemented in the context of Finite Elements while paying special attention to the choice of the energy decomposition, whereof two are implemented: No-Decomposition and No-Tension decomposition. Specifically, the latter showcases satisfactory agreement with both Finite Fracture Mechanics and Dugdale's Cohesive Zone Model, thus posing a solid contender for studying complex fracture scenarios upon combined tension-compression stress states.

Buckling Analysis of Porous Functionally Graded Plates

This study investigated the buckling behavior of Porous Functionally Graded Material (PFGM) plates. The present model assumes unevenly distributed porosity along the plate thickness and the use of the novel hyperbolic shear deformation functions and hyperbolic tangent and secant thickness stretching functions. In the present work, a porous Functionally Graded (FG) plate was analyzed by the principle of virtual work in order to understand the buckling behavior under uniaxial and biaxial compressive loading. The Rayleigh quotient method was applied to find the critical buckling load. The mesh convergence was investigated on a Finite Element (FE) model, and the accuracy of the results was compared with the prior research. The results of the proposed model match reasonably well with the ones of the published literature. Thorough parametric studies were performed to investigate the effect of porosity on the critical buckling load of the PFGM plate.

On-demand heart valve manufacturing using focused rotary jet spinning

On-demand heart valve manufacturing using focused rotary jet spinning

Comprehensive inter-fibre failure analysis and failure criteria comparison for composite materials using micromechanical modelling under biaxial loading

Inter-fibre failure analysis of carbon fibre-reinforced polymer (CFRP) composites, under biaxial loading conditions, has been a longstanding challenge and is addressed in this study. Biaxial failure analysis of IM7/8552 CFRP unidirectional (UD) composites is conducted under various stress states. Two widely accepted failure criteria, the interactive Tsai-Wu and non-interactive Hashin failure criteria, are comprehensively assessed with finite element-based micromechanical analysis. High-fidelity three-dimensional representative volume elements (RVEs) are subjected to biaxial loadings with imposed periodic boundary conditions. Carbon fibres are assumed to be transversely isotropic and linearly elastic. The Drucker-Prager plastic damage constitutive model and cohesive zone model are utilised to simulate the mechanical response of the matrix and fibre-matrix interface, respectively. Coulomb friction is assumed between the fibres and matrix after interface failure. Two sets of biaxial loading scenarios (i.e. transverse stress dominated and shear stress dominated) with the associated failure modes are selected for the failure analysis and assessment of these failure criteria. A data-driven failure envelope for the composites under biaxial loadings is developed using a univariate cubic spline function. Failure mode transition points are determined under biaxial loadings. It is found that the micromechanics-based numerical model is effective in assessing these two existing criteria.

Infrared radiation constitutive model of sandstone during loading fracture

The significant increase in energy demand will inevitably boost the exploitation of natural resources. The exploitation of resources including coal, oil, geothermal, natural gas, shale gas, and other energy has to be extracted with deep mining to fulfill the industry energy demand. With the increase of mining depth and the utilization of deep rock mass, the problem of high ground stress has become increasingly prominent. During high ground stress conditions, the mechanical behavior of hard rock will change significantly. Constructing a reasonable stress–strain damage constitutive model of hard rock is the basis for the design of a resource mining construction scheme, numerical simulation analysis, more accurate acquisition of rock mechanical characteristics, and evaluation of engineering rock stability. This is very crucial that needs to be addressed in a better way to solve the scientific problems of rock engineering. In this research, the infrared radiation observation experiments of sandstone biaxial under different lateral stresses are carried out. It is found that the infrared radiation energy has a near power function relationship with the effective stress in loading and fracture process. The quantitative characterization method of infrared radiation of the first invariant of stress and the second invariant of deviator stress is established. The cumulative high-temperature point scale factor amplitude is proposed to characterize the plastic volumetric strain of sandstone. Based on the effective stress and plastic strain, the plastic and damage models are established respectively. The three-dimensional plastic damage constitutive model of loaded sandstone based on infrared radiation is constructed. The model has clear input parameters having physical significance, and the compaction stage of sandstone is considered. The stress prediction of sandstone during biaxial loading is realized through the secondary development of a finite element software subroutine. The research results can lay a theoretical foundation for the analysis and evaluation of the mechanical characteristics of hard rock in the process of deep energy exploitation.

Calculations of biaxial fatigue limits with models using the experimental crack direction

Several models from the literature were used to predict the fatigue limit in notched components subjected to biaxial cyclic loading. The predictions of these models are based on the elastic stresses along a line which is considered to be representative of the crack direction in its initial part. The line used in the models changes considerably. For one of the studied models, the line direction corresponds to Mode I, while for another it is Mode II, and for the other two models considered the direction is between Mode I and Mode II. However, quite naturally, the experimental crack direction is unique. In recent years, a study of experimental fatigue limits and crack directions in its initial part for three materials was carried out in hollow cylindrical specimens with a circular hole subjected to cyclic axial, torsional and in-phase biaxial loading. The directions of the cracks that were measured experimentally are on average similar for the three materials and close to Mode I. The analysed models give, in general, good predictions of the experimental fatigue limits, although they use directions that are completely different and that they too differ markedly from the experimentally found ones. The predictions of the models using, in a forced way, the measured experimental directions are good in most cases, which reveals a surprising insensitivity of these models to the main hypotheses on which their own formulations are based.

Behaviour of composite solid propellant under biaxial tensile loading

Biaxial tensile tests were carried out on cruciform specimens of composite solid propellants. Digital Image Correlation (DIC) was used to measure the strain in the gage section. Experiments were conducted at displacement rates of 1, 50 and 1000 mm/min (Y direction) to study the effect of the displacement rate on the material response. Two displacement rate ratios of 1:1 and 0.5:1 (X:Y directions) are considered to understand the influence of biaxiality of loading on the mechanical response. The biaxial experiments were also conducted at temperatures of 20 °C and 55 °C to understand the effect of temperature on the material response. The stress–strain response under biaxial loading was observed to be non-linear and dependent on the displacement rate. The slope of the stress–strain response in the linear region and the yield stress increased with an increase in the displacement rate for all the loading situations. There was no significant change observed in the slope of the stress–strain response in the linear region and yield stress with variation in temperature from 20 to 55 °C. However, a significant decrease in failure strain was observed with an increase in temperature from 20 °C to 55 °C. The mechanical response under equi-biaxial (displacement rate ratio — X:Y of 1:1) loading is compared with the uniaxial loading responses. The yield stress was observed to be 25%–47% higher during equi-biaxial tests as compared to uniaxial tests. However, the failure strain was 50%–70% lower in the equi-biaxial loading compared to uniaxial loading. The fractography and elemental mapping using Energy Dispersive Spectroscopy (EDS) of the fractured surfaces were carried out. A large number of cavities which are bigger in size and depth were observed on the fractured surface of the uniaxially loaded specimens as compared to equi-biaxially loaded specimens.

Biaxial shear behavior of recycled concrete aggregate reinforced concrete beams

The study aimed to investigate the capacity of reinforced concrete beams that include Recycled Coarse Aggregates (RCA) when subjected to biaxial shear loading. Nine beams of square cross-section 300 mm x 300 mm were tested until failure under three different load inclinations angles. The specimens were divided into three groups based on the aggregate type: 100 % Natural Concrete Aggregate (NCA), 100 % RCA, and a combination of 60 % RCA and 40 % NCA. The experimental results indicated that the uniaxial shear capacity of the 60 % RCA and 40 % NCA specimen was higher by about 8 % compared to the uniaxial shear capacity of the NCA and RCA specimens. Additionally, the 60 % RCA and 40 % NCA specimens showed better performance in terms of capacity and deformation than the RCA specimens under all load inclinations. This outcome is also supported by literature investigating the flexural and uniaxial shear capacity of reinforced concrete beams that incorporate 60 % RCA and 40 % NCA. Furthermore, the study revealed that the biaxial shear capacity generally decreased as the load inclination angle increased, and there was a quadratic relationship between the biaxial shear capacity of the tested beams and the load inclination. Theoretical values of the biaxial shear capacity based on the cross-section geometry, material, and load inclination were determined using equations proposed by Tinini et al. and were found to give conservative predictions of the biaxial shear strength. Therefore, the study highly recommends the use of the 60 % RCA and 40 % NCA combination in reinforced concrete beams and the equations proposed by Tinini et al. for biaxial shear capacity.

A new damage-based failure criterion for nonlinear behavior of fibrous composite materials

In the present paper, a novel combined damage-based failure criterion is being proposed for predicting failure stresses in unidirectional fibrous composite laminas or laminates having a nonlinear material behavior. The present model incorporates the effect of a quantitative damage factor on the final stresses at failure. This is achieved through a new term called the quantitative directional damage-index (QDD-I) which assesses the contribution and effectiveness of damage in each principal material direction on the present failure criterion. From the QDD-I, it is proved that the principal material-direction with a linear or nonlinear stress-strain behavior showed a quantitative damage response on the proposed failure criterion. In a composite lamina, the contribution of fiber-damage and matrix transverse-damage are proved to have minor effects on the failure criterion, while in-plane shear-damage has the major effect. In order to verify the suitability and applicability of the criterion, results are tested using various theoretical and experimental data available from the literature. Furthermore, the model is compared with other failure criteria under both uniaxial and biaxial loading cases from a worldwide comparison, which showed reasonable accuracy and good agreement. Three types of fibrous composite materials are used; Graphite/Epoxy 4617/Modmore-II, Carbon/Epoxy AS4/3501-6, and Boron/Epoxy Narmco 5505.

Buckling of laminated composite plate with various shapes of holes under uniform/nonuniform mechanical and thermal loading

ABSTRACT In this study, buckling characteristics of laminated composite plates with different shapes of holes under uniform/nonuniform mechanical and thermal loads are investigated. Mathematical formulations are done using finite element-based first-order shear deformation theory. A MATLAB programme is developed using isoperimetric quadrilateral elements with five degrees-of-freedom per node. Uniaxial and biaxial loading on full and partial edge of the plate are considered in the analysis. Solution for buckling load is done using eigenvalue approach and detailed parametric studies revealed the influence of the aspect ratio, plate span to thickness ratio, the shape of hole, distribution of mechanical and thermal load, boundary conditions, and fibre orientation on buckling loads and temperature. The findings of this study are in good agreement with those presented in the literature, verifying the efficiency of the proposed method.

Constituent-based quasi-linear viscoelasticity: a revised quasi-linear modelling framework to capture nonlinear viscoelasticity in arteries

Arteries exhibit fully nonlinear viscoelastic behaviours (i.e. both elastically and viscously nonlinear). While elastically nonlinear arterial models are well established, effective mathematical descriptions of nonlinear viscoelasticity are lacking. Quasi-linear viscoelasticity (QLV) offers a convenient way to mathematically describe viscoelasticity, but its viscous linearity assumption is unsuitable for whole-wall vascular applications. Conversely, application of fully nonlinear viscoelastic models, involving deformation-dependent viscous parameters, to experimental data is impractical and often reduces to identifying specific solutions for each tested loading condition. The present study aims to address this limitation: By applying QLV theory at the wall constituent rather than at the whole-wall level, the deformation-dependent relative contribution of the constituents allows to capture nonlinear viscoelasticity with a unique set of deformation-independent model parameters. Five murine common carotid arteries were subjected to a protocol of quasi-static and harmonic, pseudo-physiological biaxial loading conditions to characterise their viscoelastic behaviour. The arterial wall was modelled as a constrained mixture of an isotropic elastin matrix and four families of collagen fibres. Constituent-based QLV was implemented by assigning different relaxation functions to collagen- and elastin-borne parts of the wall stress. Nonlinearity in viscoelasticity was assessed via the pressure dependency of the dynamic-to-quasi-static stiffness ratio. The experimentally measured ratio increased with pressure, from 1.03 pm 0.03 (mean pm standard deviation) at 80–40 mmHg to 1.58 pm 0.22 at 160–120 mmHg. Constituent-based QLV captured well this trend by attributing the wall viscosity predominantly to collagen fibres, whose recruitment starts at physiological pressures. In conclusion, constituent-based QLV offers a practical and effective solution to model arterial viscoelasticity.

Closed-loop Control of Biaxial Fatigue Loading of Wind Turbine Blades Based on Visual Inspection

Based on the inertial vibration excitation device, a biaxial fatigue loading system for wind turbine blades is established by using visual inspection technology and virtual spindle decoupling to control the vibration excitation motion of wind turbine blades. The image feature point tracking method is used to detect the blade vibration state. Considering the system vibration frequency characteristics, the phase difference between the exciting force and the vibration displacement is detected based on the phase detector, and the system resonance frequency is adaptively tracked to achieve accurate control of the double-free amplitude of the blade. The fatigue test shows that the control system can maintain the amplitude error of the blade, the adaptive tracking control method is reliable and effective, and the accuracy and reliability of the fatigue test are improved.

Lévy-type solutions for the buckling analysis of unsymmetrically laminated plates with rotational restraints for various plate theories

The stability behaviour of unsymmetrical laminated structures made of fibre-reinforced plastics is significantly influenced by bending–extension coupling and the comparatively low transverse shear stiffnesses. The aim of this work is to improve the analytical stability analysis of unsymmetrically laminated structures. With the discrete plate theory, the stability of laminated structures can be reduced to single laminated plates. The structure is divided into individual segments, and the surrounding structure is modelled by rotational elastic restraints. The governing equations for single plates under specific boundary conditions can be solved exactly with Lévy-type solutions. In this study, Lévy-type solutions for the mentioned boundary conditions under biaxial compressive load is described for the classical laminated plate theory, the first-order shear deformation theory and the third-order shear deformation theory (TSDT). In addition to transverse shear, bending–extension couplings of unsymmetrical cross-ply and antisymmetrical angle-ply laminates are considered. For the implementation of boundary conditions for the rotational restraints in the context of TSDT, a new set of conditions is formulated. The investigation shows very good agreement of the buckling load with comparative finite element analyses for different layups.

Damage softening constitutive model of HTPB propellant for biaxial loading

In order to establish the damage constitutive model of composite solid propellant, it is assumed that the micro element strength in HTPB propellants follows Weibull distribution. Using the twin-shear unified strength theory, a damage distribution variable is established, and a constitutive model characterizing the damage deformation process of HTPB propellants is established. Based on the biaxial loading experimental data of HTPB propellant at room temperature (298.15 K) and three loading rates (0.40 s−1, 4.00 s−1, and 14.29 s−1), the model parameters were fitted, and the relationship between the parameters in the damage constitutive model and strain rate was given. The model was validated using experimental results at room temperature (298.15 K) and three other loading rates (1.00 s−1, 2.00 s −1, and 8.00 s−1). The results show that the damage constitutive model can well describe the stress strain relationship of HTPB propellant under biaxial loading, although the model prediction effect of the nonlinear transition region of the stress strain curves is poor. Finally, it is concluded that the constitutive model established in this paper reflects the softening characteristics of HTPB propellants and the phenomenon that the strength of HTPB propellants is affected by the stress state. The damage constitutive model can provide a reference for the damage analysis of composite solid propellants under complex loading conditions.

Effects of tissue degradation by collagenase and elastase on the biaxial mechanics of porcine airways

BackgroundCommon respiratory illnesses, such as emphysema and chronic obstructive pulmonary disease, are characterized by connective tissue damage and remodeling. Two major fibers govern the mechanics of airway tissue: elastin enables stretch and permits airway recoil, while collagen prevents overextension with stiffer properties. Collagenase and elastase degradation treatments are common avenues for contrasting the role of collagen and elastin in healthy and diseased states; while previous lung studies of collagen and elastin have analyzed parenchymal strips in animal and human specimens, none have focused on the airways to date.MethodsSpecimens were extracted from the proximal and distal airways, namely the trachea, large bronchi, and small bronchi to facilitate evaluations of material heterogeneity, and subjected to biaxial planar loading in the circumferential and axial directions to assess airway anisotropy. Next, samples were subjected to collagenase and elastase enzymatic treatment and tensile tests were repeated. Airway tissue mechanical properties pre- and post-treatment were comprehensively characterized via measures of initial and ultimate moduli, strain transitions, maximum stress, hysteresis, energy loss, and viscoelasticity to gain insights regarding the specialized role of individual connective tissue fibers and network interactions.ResultsEnzymatic treatment demonstrated an increase in airway tissue compliance throughout loading and resulted in at least a 50% decrease in maximum stress overall. Strain transition values led to significant anisotropic manifestation post-treatment, where circumferential tissues transitioned at higher strains compared to axial counterparts. Hysteresis values and energy loss decreased after enzymatic treatment, where hysteresis reduced by almost half of the untreated value. Anisotropic ratios exhibited axially led stiffness at low strains which transitioned to circumferentially led stiffness when subjected to higher strains. Viscoelastic stress relaxation was found to be greater in the circumferential direction for bronchial airway regions compared to axial counterparts.ConclusionTargeted fiber treatment resulted in mechanical alterations across the loading range and interactions between elastin and collagen connective tissue networks was observed. Providing novel mechanical characterization of elastase and collagenase treated airways aids our understanding of individual and interconnected fiber roles, ultimately helping to establish a foundation for constructing constitutive models to represent various states and progressions of pulmonary disease.

Computational Model Verification and Validation of Elastoplastic Buckling Due to Combined Loads of Thin Plates

Thin plates are widely used in various engineering applications. In some cases, these structural components may buckle due to compressive loads, which can be aggravated by lateral loads. Several authors have studied the elastoplastic buckling behavior of thin plates considering parameters such as material and geometric properties, support conditions, and initial out-of-plane imperfections. Some studies have also investigated the effects of notches and holes on the ultimate buckling stress of thin plates. The main goal of the present work is to verify and validate a computational model developed using the Finite Element Method via ANSYS® software, to simulate the mechanical behavior of metallic plates under uniaxial or biaxial compression combined with lateral load. The proposed numerical model was verified and validated by comparing its results with analytical, numerical, and experimental solutions found in the literature, reaching maximum differences and errors of around 5%. In sequence, the verified and validated computational model was used in a simple case study: a simply supported plate with a centered rectangular perforation and subjected to an in-plane compressive biaxial load combined with a lateral load, considering five different metallic materials: AISI 4130 steel, AH-36 steel, spheroidal graphite iron (SGI), compact graphite iron (CGI) and Al 7075-T651 aluminum alloy. The results obtained are consistent and, as expected, prove the applicability of the proposed computational model. From this, the biaxial elastoplastic buckling behavior was evaluated, indicating that among the studied cases the higher ultimate stress and the smallest maximum deflection were achieved, respectively, by the plates made of AISI 4130 steel and AH-36 steel.

ASSESSMENT OF TIBIOFEMORAL AND ALLOGRAFT LOADING AFTER OSTEOCHONDRAL ALLOGRAFT TRANSPLANTATION USING SHELL GRAFTS

In this study, we aimed to investigate tibiofemoral and allograft loading parameters after OCA transplantation using tibial plateau shell grafts to characterize the clinically relevant biomechanics that may influence joint kinematics and OCA osseointegration after transplantation. The study was designed to test the hypothesis that there are significant changes in joint loading after tibial plateau OCA transplantation that may require unique post-operative rehabilitation regimens in patients to restore balance in the knee joint.Fresh-frozen cadaveric knees (n=6) were thawed and mounted onto a 6 DOF KUKA robot. Specimens were size matched to +2 mm for the medial-to-lateral width of the medial tibial hemiplateaus. Three specimens served as allograft recipient knees and three served as donor knees. Recipient knees were first tested in their native state and then tested with size-matched medial tibial hemiplateau shell grafts (n=3) prepared from the donor knees using custom-cut tab-in-slot and subchondral drilling techniques. Tekscan sensors were placed in the joint spaces to evaluate the loading conditions under 90N biaxial loading at full extension of the knee before and after graft placement. The I-Scan system used in conjunction analyzed the total force, pressure distribution, peak pressure, and center of force within the joint space.Data demonstrated significant difference (p<0.05) in joint space loading after graft implantation compared to controls in both lateral and medial tibial plateaus. The I-Scan pressure mapping system displayed changes in femoral condylar contact points as well.The results demonstrated that joint space loading was significantly different (p<0.05) between all preoperative and postoperative cadaveric specimens. Despite the best efforts to size match grafts, slight differences in the host's joint geometry resulted in shifts of contact areas between the tibial plateau and femoral condyle therefore causing either an increase or decrease in pressure measured by the sensor. This concludes that accuracy in graft size matching is extremely important to restoring close to normal loading across the joint and this can be further ensured through postoperative care customized to the patient after OCA surgery.