Flexural and Shear Deformation of Basement-Clamped Reinforced Concrete Shear Walls.

For a precise analysis of buildings under earthquake effects, the load-deformation behaviour of the bracing walls must be comprehensively known. The horizontal bracing walls are often clamped in the basement; however, less attention has been paid to these walls' clamping parts in the past. This study presents three shear wall experiments (NW 1, NW 2, NW 3) with heights up to six meters in a scale of 1:1.5 to the real size. Measured were the force-displacement curve, the curvature distribution over the height, the crack pattern, and the crack opening and spacing. Twelve displacement transducers, an optical measurement system with eight cameras, and a manual crack measurement were utilised. Out of the measurements, the impact of the tension shift effect on the load-displacement curves could be quantified for the cantilever part of the walls. Additionally, it was found out that a sliding failure in the clamping part must be considered if the aspect ratio of H/L is equal to or less than one.

Mechanical Properties of Fully Recycled Aggregate Concrete Reinforced with Steel Fiber and Polypropylene Fiber.

The study and utilization of fully recycled aggregate concrete (FRAC), in which coarse and fine aggregates are completely replaced by recycled aggregates, are of great significance in improving the recycling rate of construction waste, reducing the carbon emission of construction materials, and alleviating the ecological degradation problems currently faced. In this paper, investigations were carried out to study the effects of steel fiber (0.5%, 1.0%, and 1.5%) and polypropylene fiber (0.9 kg/m3, 1.2 kg/m3 and 1.5 kg/m3) on the properties of FRAC, including compressive strength, splitting tensile strength, the splitting tensile load-displacement curve, the tensile toughness index, flexural strength, the load-deflection curve, and the flexural toughness index. The results show that the compressive strength, splitting tensile strength, and flexural strength of fiber-reinforced FRAC were remarkably enhanced compared with those of ordinary FRAC, and the maximum increase was 56.9%, 113.3%, and 217.0%, respectively. Overall, the enhancement effect of hybrid steel-polypropylene fiber is more significant than single-mixed fiber. Moreover, the enhancement of the crack resistance, tensile toughness, and flexural toughness obtained by adding steel fiber to the FRAC is more significant than that obtained by adding polypropylene fiber. Furthermore, adding polypropylene fiber alone and mixing it with steel fiber showed different FRAC splitting tensile and flexural properties.

Effect of glenohumeral ligaments on posterior shoulder stabilization: a biomechanical study.

OBJECTIVES: To theoretically confirm that the glenohumeral ligament (GHL), specifically the inferior glenohumeral ligament (IGHL), plays an important role in posterior shoulder stability in different postures, and to provide reference for clinical diagnosis and treatment of posterior shoulder instability (PSI). MATERIALS AND METHODS: In this retrospective study, bone-ligament-bone models were established in 15 fresh adult shoulder joint specimens and selective cutting was performed for analysis. The humeral head was loaded posteriorly at a central pressure of 22N using the INSTRON8874 biomechanical testing system and the load-displacement curve was plotted. The posterior displacement of the humeral head was measured after continuous cutting of the following structures: (1) complete; (2) superior glenohumeral ligament (SGHL); (3) SGHL + middle glenohumeral ligament (MGHL); (4) SGHL + MGHL + IGHL; (5) MGHL; (6) MGHL + IGHL; (7) anterior-bundle IGHL (IGHL-AB); (8) posterior-bundle IGHL (IGHL-PB); (9) IGHL. The results obtained were analyzed using the SPSS10.0 statistical software. RESULTS: Favorable posterior stability of the complete bone-ligament-bone model was observed, with an average displacement of 11.32±3.89 mm. The displacement of SGHL and SGHL + MGHL groups was not significantly increased compared with that in the complete group (P>0.05). After cutting of SGHL + MGHL + IGHL, the posterior displacement of all angles increased (P<0.05), resulting in PSI that was manifested in dislocation or subluxation. There was no obvious increase in posterior displacement after cutting the IGHL-AB (P>0.05). Significantly increased posterior displacement was observed at 45° abduction after cutting the IGHL-PB compared with the complete group, but not at the 90° abduction. The posterior displacement increased obviously at both 45° and 90° abduction when the IGHL was completely cut off (P<0.05). CONCLUSIONS: Repairing the IGHL plays a certain role in rebuilding the posterior stability of the shoulder joint. Detecting the function of the IGHL in the abduction and external rotation positions of the shoulder joint has certain significance for diagnosing PSI.

Subregional analysis of joint stiffness facilitates insight into ligamentous laxity after ACL injury.

Purpose: Increased incidence of anterior cruciate ligament injuries has amplified the need for quantitative research in clinical and academic settings. We used a novel digital arthrometer to measure knee laxity in healthy people and patients with anterior cruciate ligament injuries. Changes in stiffness were also assessed to develop new indicators for detecting anterior cruciate ligament injury. The purpose of this study was to use arthrometer to measure the quantitative indicator of knee laxity, bringing clinicians a new perspective on how to identify injury to the ACL. Methods: In this cross-sectional study, anterior tibial displacement under continuous loading was measured using a novel digital arthrometer in 30 patients with unilateral anterior cruciate ligament injury and 30 healthy controls. Load-displacement curves were plotted, using real-time load and displacement changes. Stiffness was defined by the slope of the applied load to tibial displacement. Anterior tibial displacement and instantaneous stiffness values under different loads were compared. The restricting contribution of the anterior cruciate ligament transformed the displacement-stiffness curve from a sharp decrease to a stable increase, resulting in a minimum stiffness value. Using the minimum stiffness as the turning point, the load-displacement curve was divided into regions 1 and 2. The two regions' stiffness changes were compared. Based on the findings, receiver operating characteristic curves were plotted and the area under the curve was calculated to estimate the diagnostic accuracy. Results: Anterior tibial displacement was significantly greater in the anterior cruciate ligament injury group than in the controls under each 10-N increase load (p < 0.05). In the anterior cruciate ligament injury group, instantaneous stiffness was significantly lower on the injured side than on the healthy side (p < 0.05). In the two regions of the load-displacement curve, stiffness was significantly lower in the anterior cruciate ligament injury group than in the control group (all, p < 0.05). Receiver operating characteristic curves were plotted, using changes in stiffness under the two regions in both groups. Stiffness in region 2 had the largest area under the curve (0.94; 95% CI, 0.88-0.99). Using the cut-off value of 9.62 N/mm to detect ACL injury, the sensitivity and specificity were 93% and 82%, respectively. Conclusion: Our investigation of ligament stiffness provides novel insights into the properties of knee laxity. Stiffness in the later stages of increased loading <9.62 N/mm could be a valid indicator for identifying knee laxity.

Compressive Mechanical Properties of Larch Wood in Different Grain Orientations.

As a green and low-carbon natural polymer material, wood has always been popular in engineering applications owing to its excellent physical and mechanical properties. In this study, compression tests in conjunction with in situ test methods (DIC method) were used to investigate the compression mechanism of wood samples in the longitudinal, radial, and tangential directions. The macroscopic failure modes, energy dissipation results, and variations in the strain field were analyzed. The results showed that the load-displacement curve in each grain orientation included three stages: an elasticity stage, yield stage, and strengthening stage. Both the compressive strength and elastic modulus in the longitudinal direction were significantly higher than those in the radial and tangential directions, but there was no significant difference between the radial and tangential directions. Specimens in the longitudinal direction mainly presented fiber buckling, fiber shear slippage, and fiber fracture failure; in radial directions mainly presented compression compaction of the fiber cells; and in the tangential directions presented buckling and shear failure of the laminar layers. The energy absorption in the longitudinal direction was better than in the other directions. The strain changed significantly in the loading direction in the elastic stage while the shear strain changed remarkably in the yield stage in each grain orientation. In this paper, the compression mechanical properties of larch wood in different grain orientations were studied to provide a reference for its safe application in engineering.

Quantitative analysis with load-displacement ratio measured via digital arthrometer in the diagnostic evaluation of chronic ankle instability: a cross-sectional study.

BACKGROUND: Arthrometry has been introduced to evaluate the laxity of ankle joint in recent years. However, its role in the diagnosis of chronic ankle instability is still debatable. Therefore, we assessed the diagnostic accuracy of a digital arthrometer in terms of sensitivity and specificity. METHODS: According to the inclusion and exclusion criteria proposed by the International Ankle Consortium, we recruited 160 uninjured ankles (control group) and 153 ankles with chronic ankle instability (CAI group). Ankle laxity was quantitively measured by a validated digital arthrometer. Data of loading force and joint displacement were recorded in a continuous manner. Differences between the control and CAI groups were compared using 2-tailed independent t test. A receiver operating characteristic curve analysis was used to calculate area under a curve, sensitivity and specificity. RESULTS: Load-displacement curves of the two groups were depicted. Differences of joint displacement between the control and CAI groups were compared at 30, 45, 60, 75, 90, 105 and 120 N, which were all of statistical significance (all p < 0.001) with the largest effect size at 90 N. Statistical significance was found in the differences between the two groups in load-displacement ratio at 10-120 N, 10-40 N, 40-80 N and 80-120 N (all p < 0.001), with the largest effect size at 10-40 N. Load-displacement ratio at the interval of 10-40 N had the highest area under a curve (0.9226), with sensitivity and specificity of 0.804 and 0.863, respectively, when the cutoff point was 0.1582 mm/N. CONCLUSION: The digital arthrometer measurement could quantitively analyze the ankle laxity with high diagnostic accuracy. The load-displacement ratio would be a reliable and promising approach for chronic ankle instability diagnosis. Level of evidence level II.

Experimental dataset for the macro-scale compression of Norway Spruce perpendicular to grain direction.

This article presents load and displacement data of Norway Spruce quasi-static compression test as well as video recordings of the experiment using the Universal Testing Machine (UTM). The specimens are 4 cm × 4 cm × 8 cm clear-wood cuboids with grain direction perpendicular to and loading direction parallel to the long axis. Due to the radially-arranged annual ring at such scale of the specimens, the plane of interest features significantly-varying orientation of the weak axes, namely the radial (R) and tangential (T) directions. A hemispherical knee joint underneath the specimen were fine-adjusted under preload before each experiment to ensure evenly-distributed load. Additionally, grids of 5 mm spacing were drawn on the plane of interest for better clarity of the deformed shape. Both load and displacement history recorded by the UTM as well as the deformation process recorded as video may provide valuable information for validation of wood material models or simulation methods with wood material implementations.

Compressive Failure Mechanism of Structural Bamboo Scrimber.

Bamboo scrimber is one of the most popular engineering bamboo composites, owing to its excellent physical and mechanical properties. In order to investigate the influence of grain direction on the compression properties and failure mechanism of bamboo scrimber, the longitudinal, radial and tangential directions were selected. The results showed that the compressive load-displacement curves of bamboo scrimber in the longitudinal, tangential and radial directions contained elastic, yield and failure stages. The compressive strength and elastic modulus of the bamboo scrimber in the longitudinal direction were greater than those in the radial and tangential directions, and there were no significant differences between the radial and tangential specimens. The micro-fracture morphology shows that the parenchyma cells underwent brittle shear failure in all three directions, while the fiber failure of the longitudinal compressive specimens consisted of ductile fracture, and the tangential and radial compressive specimens exhibited brittle fracture. This is one of the reasons that the deformation of the specimens under longitudinal compression was greater than those under tangential and radial compression. The main failure mode of bamboo scrimber under longitudinal and radial compression was shear failure, and the main failure mode under tangential compression was interlayer separation failure. The reason for this difference was that during longitudinal and radial compression, the maximum strain occurred at the diagonal of the specimen, while during tangential compression, the maximum strain occurred at the bonding interface. This study can provide benefits for the rational design and safe application of bamboo scrimber in practical engineering.

The Fabrication and Indentation of Cubic Silicon Carbide Diaphragm for Acoustic Sensing.

In this study, 550 nm thick cubic silicon carbide square diaphragms were back etched from Si substrate. Then, indentation was carried out to samples with varying dimensions, indentation locations, and loads. The influence of three parameters is documented by analyzing load-displacement curves. It was found that diaphragms with bigger area, indented at the edge, and low load demonstrated almost elastic behaviour. Furthermore, two samples burst and one of them displayed pop-in behaviour, which we determine is due to plastic deformation. Based on optimum dimension and load, we calculate maximum pressure for elastic diaphragms. This pressure is sufficient for cubic silicon carbide diaphragms to be used as acoustic sensors to detect poisonous gasses.

Optimal Distraction Force for Evaluating Tibiofemoral Joint Gaps in Posterior Stabilized Total Knee Arthroplasty.

BACKGROUND: Obtaining well-balanced soft tissues is important to achieve natural knee kinematics after total knee arthroplasty (TKA). In conventional procedures, soft tissue balance is evaluated with spacer blocks or lamina spreaders. However, the evaluation depends on the surgeons' experience and is not quantitative. This study aims to measure the mechanical properties of knee soft tissue with a new ligament balancer and to determine the optimal distraction force for evaluating tibiofemoral joint gaps in TKA. METHODS: This study included 30 consecutive patients with medial knee osteoarthritis who were scheduled to undergo posterior stabilized TKA. The mean age of patients was 73 ± 9.6 years at the time of surgery, and the mean hip-knee-ankle angle was 13.1 ± 6.5° in varus. After distal femoral and proximal tibial resections, the tibiofemoral joint gaps under several distraction forces were measured in extension and at 90° flexion. The load-displacement curves in extension and flexion were drawn with these data, and the stability range, which was defined as the shift range from the toe region to the linear region in the curves, was calculated. RESULTS: The stability ranges were 160 Newtons (N) in extension and 140 N in flexion. CONCLUSIONS: These displacement forces were considered optimal for evaluating tibiofemoral joint gaps during surgery and ensuring knee stability after TKA.

Experimental data on the development of "Post-installed Screw Pullout test" for in-situ investigation of concrete strength.

This data article describes the datasets obtained during the development phase of "Post-installed Screw Pullout (PSP) test", a new in-situ test for concrete strength assessment. The datasets presented focus on the results obtained in mortar samples. The presented PSP test method is based on a post-installed screw being pulled from the parent material. To implement this, the screws installed in mortar sample were loaded to failure and the responses were recorded in the form of load-displacement curves. The samples were tested for two types of screw under different test conditions, with variables that included hole depth, hole diameter and mortar strength. These datasets are associated with the article "The Post-installed Screw Pullout Test: Development of a Method for Assessing In-situ Concrete Compressive Strength" (Al-Sabah et al., 2020).

Load-displacement experimental data from axial tensile loading of CFRP-SPCC hybrid laminates.

The current paper shows a data set of load-displacement output from axial tensile loading of CFRP-SPCC hybrid laminates. The specimen geometries are cut based on standard procedure from ASTM D-3039. At least 3 positions in each specimen, we measured its width and thickness. Data of the load and displacement were repeated at least 3 samples in each combination of hybrid laminates. Tensile test was conducted with a 1 mm/min of loading rate. The data were recorded from unloading until failure of specimens. The data gives information about the highest load and the behavior of load-displacement in axial tensile loading. By using width and thickness, normalized data can be obtained, the load can be calculated into stress (MPa) unit. The data are useful for researchers and structural engineers that deals with CFRP, SPCC, and hybrid CFRP-SPCC laminates.

Optimal cutoff score for patient-reported outcome measures after anterior cruciate ligament reconstruction using load-displacement curve analysis.

To assess psychological components after anterior cruciate ligament (ACL) injury, we developed a new patient-reported outcome measure, the Japanese anterior cruciate ligament injury questionnaire 25 (JACL-25), and demonstrated that the JACL-25 is valid, reliable, and sufficiently responsive to evaluate psychological factors that are associated with outcomes in individuals with ACL injuries. The purpose of this study was to identify the optimum cutoff score for the JACL-25 that indicates successful clinical outcomes, combining with the graphical data obtained using the KT-2000. We studied 30 patients who underwent primary ACL reconstruction with a patella tendon or hamstring tendon autograft. On the same day of the JACL-25 evaluation, anterior knee laxity tests were performed using the KT-2000 arthrometer. ACL stiffness was calculated on the graphs of the hysteresis, which can be used to measure side-to-side differences in anterior translation. Akaike's information criterion (AIC) was used to determine the most appropriate cutoff level for the JACL-25 score for the stiffness reduction ratio and anterior-posterior (AP) translation. The average JACL-25 score was 23.8 (standard deviation (SD) 18.4). The average side-to-side displacement difference in AP translation was 2.4 (SD 4.2) mm. The average stiffness reduction ratio was 24.4% (SD 31.8). The smallest AIC values for the cutoff level for the JACL-25 score, the stiffness reduction ratio, and side-to-side differences of the anterior translation were 9, 27%, and 1.1 mm, respectively. We determined the optimal cutoff score for the JACL-25 that identifies successful clinical outcomes.

Accounting for unintended consequences of resource policy: Connecting research that addresses displacement of environmental impacts.

Natural resource policies enacted to protect environmental integrity play an important role in promoting sustainability. However, when resources are shared ecologically, economically, or through a common, global interest, policies implemented to protect resource sustainability in one domain can displace, and in some cases magnify, environmental degradation to other domains. Although such displacement has been recognized as a fundamental challenge to environmental and conservation policy within some resource sectors, there has been little cross-disciplinary and cross-sectoral integration to address the problem. This suggests that siloed knowledge may be impeding widespread recognition of the ubiquity of displacement and the need for mitigation. Here, we connect research across multiple disciplines to promote a broader discussion and recognition of the processes and pathways that can lead to displaced impacts that countermand or undermine resource policy and outline a number of approaches that can mitigate displacement.

Construction of Spine Biomechanical Test System Based on LabVIEW and Six-Axis Robot Arm and Preliminary Reliability Study / 医用生物力学

Objective To construct a new biomechanical testing system of in vitro spine based on LabVIEW and six-axis robot arm and conduct preliminary reliability studies, so as to make preparation for further studies on coupled motion testing. Methods By programming on LabVIEW platform, using Ethernet and Profibus to communicate the data of the robot arm with PC in real time, the displacement control and load control were realized, and the end position and rotation angle of the robot arm were read in real time. Through the force/torque sensor and data acquisition (DAQ), board DAQ, processing, storage and other functions were acquired. Using the digital micrometer and special stationary fixture, the 6-direction translation accuracy test was completed, and the data were analyzed. The flexion, extension, lateral flexion and rotation were applied on sheep spine specimen to draw the load-displacement curve, analyze and compare the experimental result, and verify the effectiveness of the biomechanical platform. Results A biomechanical test system with high precision for spine in vitro based on LabVIEW and 6-axis robot arm was developed and established, of which the average translational precision was 8.1 μm and the average translational accuracy was 56.7 μm. The program of control, data acquisition, data processing and storage were written, and the biomechanical test of the sheep spine was completed effectively. Conclusions This biomechanical test system based on Labview and 6-axis robot arm could complete the conventional three-dimensional spinal motion test with high precision and be used to conduct coupled motion test research in the next step.

Experimental Investigations on the Pull-Out Behavior of Tire Strips Reinforced Sands.

Waste tires have excellent mechanical performance and have been used as reinforcing material in geotechnical engineering; however, their interface properties are poorly understood. To further our knowledge, this paper examines the pull-out characteristics of waste tire strips in a compacted sand, together with uniaxial and biaxial geogrids also tested under the same conditions. The analysis of the results shows that the interlocking effect and pull-out resistance between the tire strip and the sand is very strong and significantly higher than that of the geogrids. In the early stages of the pull-out test, the resistance is mainly provided by the front portion of the embedded tire strips, as the pull-out test continues, more and more of the areas towards the end of the tire strips are mobilized, showing a progressive failure mechanism. The deformations are proportional to the frictional resistance between the tire-sand interface, and increase as the normal stresses increase. Tire strips of different wear intensities were tested and presented different pull-out resistances; however, the pull-out resistance mobilization patterns were generally similar. The pull-out resistance values obtained show that rubber reinforcement can provide much higher pull-out forces than the geogrid reinforcements tested here, showing that waste tires are an excellent alternative as a reinforcing system, regardless of the environmental advantages.

A new method to approximate load-displacement relationships of spinal motion segments for patient-specific multi-body models of scoliotic spine.

Load-displacement relationships of spinal motion segments are crucial factors in characterizing the stiffness of scoliotic spine models to mimic the spine responses to loads. Although nonlinear approach to approximation of the relationships can be superior to linear ones, little mention has been made to deriving personalized nonlinear load-displacement relationships in previous studies. A method is developed for nonlinear approximation of load-displacement relationships of spinal motion segments to assist characterizing in vivo the stiffness of spine models. We propose approximation by tangent functions and focus on rotational displacements in lateral direction. The tangent functions are characterized using lateral bending test. A multi-body model was characterized to 18 patients and utilized to simulate four spine positions; right bending, left bending, neutral, and traction. The same was done using linear functions to assess the performance of the proposed tangent function in comparison with the linear function. Root-mean-square error (RMSE) of the displacements estimated by the tangent functions was 44 % smaller than the linear functions. This shows the ability of our tangent function in approximation of the relationships for a range of infinitesimal to large displacements involved in the spine movement to the four positions. In addition, the models based on the tangent functions yielded 67, 55, and 39 % smaller RMSEs of Ferguson angles, locations of vertebrae, and orientations of vertebrae, respectively, implying better estimates of spine responses to loads. Overall, it can be concluded that our method for approximating load-displacement relationships of spinal motion segments can offer good estimates of scoliotic spine stiffness.

Biomechanical comparison of short-segment posterior fixation including the fractured level and circumferential fixation for unstable burst fractures of the lumbar spine in a calf spine model.

OBJECTIVE There has been a transition from long- to short-segment instrumentation for unstable burst fractures to preserve motion segments. Circumferential fixation allows a stable short-segment construct, but the associated morbidity and complications are high. Posterior short-segment fixation spanning one level above and below the fractured vertebra has led to clinical failures. Augmentation of this method by including the fractured level in the posterior instrumentation has given promising clinical results. The purpose of this study is to compare the biomechanical stability of short-segment posterior fixation including the fractured level (SSPI) to circumferential fixation in thoracolumbar burst fractures. METHODS An unstable burst fracture was created in 10 fresh-frozen bovine thoracolumbar spine specimens, which were grouped into a Group A and a Group B. Group A specimens were instrumented with SSPI and Group B with circumferential fixation. Biomechanical characteristics including range of motion (ROM) and load-displacement curves were recorded for the intact and instrumented specimens using Universal Testing Device and stereophotogrammetry. RESULTS In Group A, ROM in flexion, extension, lateral flexion, and axial rotation was reduced by 46.9%, 52%, 49.3%, and 45.5%, respectively, compared with 58.1%, 46.5%, 66.6%, and 32.6% in Group B. Stiffness of the construct was increased by 77.8%, 59.8%, 67.8%, and 258.9% in flexion, extension, lateral flexion, and axial rotation, respectively, in Group A compared with 80.6%, 56.1%, 82.6%, and 121.2% in Group B; no statistical difference between the two groups was observed. CONCLUSIONS SSPI has comparable stiffness to that of circumferential fixation.

Effects of reactive oxygen species on the physical properties of polypropylene surgical mesh at various concentrations: a model for inflammatory reaction as a cause for mesh embrittlement and failure.

BACKGROUND: Oxidative degradation by reactive oxygen species (ROS) from inflammation initiates cross-linking, depolymerization, and formation of a quasi-crystalline quality in polypropylene (PP) meshes that cause embrittlement (J Urol 188:1052, 2012). Embrittlement leads to change in tensile strength and is associated with post-operative complications that include pain, adhesion, dislodgment, and fragmentation. METHODS: A laboratory environment was constructed to study the relationship between concentration of ROS and change in tensile strength. Samples of Ethicon Ultrapro© PP mesh were exposed to 1 mM, 0.1 M, or 1 M hydrogen peroxide solutions for 6 months and were subjected to load displacement tensile testing (LDTT) and compared to unexposed (0 M) meshes of the same brand. RESULTS: Load at failure and elongation to failure after LDTT were determined with 95 % confidence interval. For unexposed (0 M) samples, tensile strength was 28.0 ± 2.4 lbf and elongation to failure was 2.0 ± 0.3 in. For samples exposed to 1 mM, tensile strength was 19.2 ± 1.1 lbf and the elongation to failure was 2.0 ± 0.1 in. For samples exposed to 0.1 M, tensile strength was 19.3 ± 1.6 lbf and elongation to failure was 1.9 ± 0.1 in. For samples exposed to 1 M, tensile strength was 20.7 ± 1.2 lbf and elongation to failure was 0.47 ± 0.02 in. CONCLUSION: The results demonstrated that a 6-month exposure to a physiologic range of ROS (1 mM) decreased tensile strength of PP mesh by 31 %. 1 mM and 0.1 M samples behaved similarly demonstrating properties of a quasi-crystalline nature. 1 M samples displayed qualities of extreme embrittlement. Scanning electron microscopy (SEM) observed fiber changes. 1 M meshes had features of brittle materials. Knowledge of changes in physical properties of PP meshes is useful for considerations for the development of a more biocompatible surgical mesh.

Construction and identification of humerus three-dimensional finite element model in children / 中国组织工程研究

BACKGROUND:Mechanical experiment of finite element numerical simulation is the effective method to research the biomechanical structure of human body. OBJECTIVE:To establish the three-dimensional finite element model of a normal 6-year-old child’s humerus. METHODS:CT images of a 6-year-old child volunteer were imported to the Mimics 10.01 software. The threshold segmentation method was used to rebuild the humerus three-dimensional model. The surface optimization treatment and surface patches dicision were performed on the surface of the model with Geomagic Studio 12.0 software. Then the mesh generation was completed in the software TrueGrid. Final y, the material properties were set and the finite element model was completed. The boundary conditions and constrains were exerted to simulate the three-point-bending test of humeurs. After the simulation, the results were outputted. RESULTS AND CONCLUSION:The humerus finite element model included 3 024 nodes and 18 758 nodes-hexahedron elements. The 0.01 m/s and 3 m/s dynamic loads were loaded respectively, then the central humerus fracture occurred and the load-displacement curve was close to the cadaver test results. The simulation results show that the simulation results of children humerus finite element model are close to the cadaver’s test, and the finite element simulation method can simulate the physical properties of the human skeleton very wel .