Mm Of Deformation Research Articles

Analysis of the Mechanical Behavior of Porcine Graft Fixation in a Polyurethane Block Using a 3D-printed PLA Interference Screw.

Objective The interest in using 3D printing in the healthcare field has grown over the years, given its advantages and potential in the rapid manufacturing of personalized devices and implants with complex geometries. Thus, the aim of the present study was to compare the mechanical fixation behavior of a 3D-printed interference screw, produced by fused deposition modeling of polylactic acid (PLA) filament, with that of a titanium interference screw. Methods Eight deep flexor porcine tendons, approximately 8 mm wide and 9 cm long, were used as graft and fixed to a 40 pounds-per-cubic-foot (PCF) polyurethane block at each of its extremities. One group was fixed only with titanium interference screws (group 1) and the other only with 3D-printed PLA screws (BR 20 2021 018283-6 U2) (group 2). The tests were conducted using an EMIC DL 10000 electromechanical universal testing machine in axial traction mode. Results Group 1 (titanium) obtained peak force of 200 ± 7 N, with mean graft deformation of 8 ± 2 mm, and group 2 (PLA) obtained peak force of 300 ± 30 N, and mean graft deformation of 7 ± 3 mm. Both the titanium and PLA screws provided good graft fixation in the polyurethane block, with no slippage or apparent deformation. In all the samples, the test culminated in graft rupture, with around 20 mm of deformation in relation to the initial length. Conclusion The 3D-printed PLA screw provided good fixation, similar to that of its titanium counterpart, producing satisfactory and promising results.

Evaluation study of pull-out capacity and deformation of bored pile foundation in a Jakarta building construction project

This study uses the finite element method to determine the value of deformation and Pullout Capacity on the Bored Pile. The results compared the calculation of the value of the deformation and Pullout Capacity on the Bored Pile with the finite element method with the pullout test results. The research method used finite element modeling and manual calculations. The results achieved in this study are that Soft Soil & Hard Soil modeling 6.47 mm for deformation and 267.495 tons for Pullout Capacity is closer to the actual value and MC Modelling is 9.08 mm for deformation and 268.497 tons for Pullout Capacity, which is the farthest modeling the actual value with a difference of approximately 50%. This is due to differences in correlation and actual soil type conditions between modeling and field conditions, because the finite element method modeling is assumed to be a perfect pile.

Weight-Bearing Restrictions With Distal Radius Wrist-Spanning Dorsal Bridge Plates

The fixation of comminuted distal radius fractures using wrist-spanning dorsal bridge plates has been shown to have good postoperative results. We hypothesized that using a stiffer bridge plate construct results in less fracture deformation with loads required for immediate crutch weight bearing. We created a comminuted, extra-articular fracture in 7 cadaveric radii, which were fixed using dorsal bridge plates. The specimens were positioned to simulate crutch/walker weight bearing and axially loaded to failure. The axial load and mode of failure were measured using 2- and 5-mm osteotomy deformations as cutoffs. Bearing 50% and 22% of the body weight was representative of the force transmitted through crutch and walker weight bearing, respectively. The load to failure at 2-mm deformation was greater than 22% body weight for 2 of 7 specimens and greater than 50% for 1 of 7 specimens. The load to failure at 5-mm deformation was greater than 22% body weight for 6 of 7 specimens and greater than 50% for 4 of 7 specimens. The mean load to failure at 2-mm gap deformation was significantly lower than 50% body weight (110.4 N vs 339.2 N). The mean load to failure at 5-mm deformation was significantly greater than 22% body weight (351.8 N vs 149.2 N). All constructs ultimately failed through plate bending. All constructs failed by plate bending at forces not significantly greater than the 50% body weight force required for full crutch weight bearing. The bridge plates supported forces significantly greater than the 22% body weight required for walker weight bearing 6 of 7 times when 5 mm of deformation was used as the failure cutoff. Elderly, walker-dependent patients may be able to use their walker as tolerated immediately after dorsal bridge plate fixation for extra-articular fractures. However, patients should not be allowed to bear full weight using crutches immediately after bridge plating.

Extension twist deformation response of an auxetic cylindrical structure inspired by deformed cell ligaments

Recent advances in artificial metamaterials have allowed unique structures to deform in distinct modes not previously found in traditional material form. Auxetic structures that induce twist through deformation have been a focus of recent research. In this paper a cell-based tubular structure with pre-deformed ligaments is proposed which exhibits efficient extension induced twist (EIT) without the limitations of buckling. An analytical model of the structure is proposed using cell parameters to characterize the non-linear twist-deformation relationship. Samples of the structure were fabricated using the Ultimaker 3 platform with elastomer based TPU 95a build material and PVA support material. The analytical model and FEM were validated by tensile experiments, where fabricated samples reached 60 degrees of non-linear axial twist over 40 mm of deformation. In order to further characterize the structure’s twist response, key design parameters of the lattice structure were varied and modelled. Actuation through tensile elastic deformation has key advantages in reliability and reduced complexity. Due to these advantages, this technology has potential applications in aerospace, biomedical and robotic fields.

ANALISIS DAMPAK GAYA TUMBUKAN MELALUI PERUBAHAN BENTUK SEGI CRUSH INITIATOR PADA STRUKTUR TAILOR-WELDED BLANK

Tailor-welded blank (TWB) structure is one of the vehicle component models used in vehicle parts. In addition, these structures can be used in crashworthiess technology which can reduce injuries during a collision.. The structure of a vehicle that has greater strength can cause passengers to be thrown from the passenger compartment. This paper discusses the effect of faceted holes such as square, hexagonal and octagonal as crush initiator mounted on TWB which results in a maximum impact force (Fmax). The smallest maximum impact force is the criteria achieved from this study. The method used experimental quasi-static loading of the actuator speed of 0.5 mm/s to achieve 9.5 mm of deformation. TWB was made from plate formation with a process of stamping to spot weld. The result showed that the maximum impact force has an increase directly proportional to the addition of the shape of the crush initiator in the amount of 14.633 kN to 18.705 kN. From these results, it can be seen a square hole as best design in obtaining the smallest maximum impact force.

Development process for a higher capacity Propsetter® system

As longwall tailgate support technologies continue to be developed and improved, strata worldwide has worked to design and manufacture a revised Propsetter to provide additional support capacity and enable applications at greater mine heights. The support is targeted for tailgate applications, however, it can also be utilized for roof support in various types of mining environments. This paper describes the design changes for enhancing the support capacity of the Propsetter to more closely align its performance with other support technologies currently being employed in longwall tailgates. Balancing changes to each design aspect of the Propsetter was key to successfully improving the roof support’s load capacity while maintaining controlled deformation. Increasing the load capacity would allow a mine to improve support efficiency with a smaller, less intrusive support compared to support alternatives and reduce the cost per foot of supported entry. The target support capacity was 711–890 kN at 50 mm of deformation to more closely match the performance of competing tailgate supports such as the 610 mm-diameter CAN®. To achieve this goal, changes were made to all design aspects of the Propsetter: diameter, wedge cut depth and angle, pod size, and confinement rings. Test results from the NIOSH Mine Roof Simulator verified that these design changes were successful in increasing the capacity of the Propsetter to the 711–890 kN range at fifty mms of deformation.

Path‐Dependent Frost‐Wedging Experiments in Fractured, Low‐Permeability Granite

AbstractTo investigate the mechanism of frost wedging in fractured low‐porosity bedrock, we monitored the opening of an artificial 4 mm wide and 80 mm deep crack, cut 20 mm from the end of a rectangular granite block. Two freezing protocols were employed – top‐down and bottom‐up, the former consisting of short‐ and long‐term variants, lasting 1 and 53 days, respectively. Our results demonstrate that (i) in 1‐day experiments, maximum crack widening during top‐down freezing is around 0.11 mm, while bottom‐up freezing produces only 0.02 mm of deformation; (ii) neither ice nor water pressure causes measurable irreversible crack widening during 1‐day tests; (iii) irreversible crack widening is only observed following the 53‐day experiment under top‐down freezing. Based on these results, we suggest (i) freezing direction plays a key role in determining the magnitude of crack widening; and (ii) freezing duration could be essential for crack propagation. The fracturing is both time‐dependent and subcritical; thus, persistent freezing in winter could actually be the active period of crack propagation. This allows us to propose a simplified method to calculate ice pressure according to crack widening. Here we show how freezing direction and duration in ice‐filled cracks control the path‐dependent efficacy of frost‐wedging. Copyright © 2017 John Wiley & Sons, Ltd.

Performance Evaluation of a Plastic Foundation for Sewage Pipeline

Abstract Earth pressure (i.e., the overburden pressure caused by hydraulic pressure and vehicle traffic loads) affects sewage pipelines. In particular, backfill materials and the execution of works considerably affect the amount of damage to sewage pipelines. A plastic foundation has been developed to reduce this damage. The load-deformation test results obtained using a universal testing machine show that the load of a rigid concrete pipe (a typical rigid pipe) increased when the contact angle of the lightweight plastic foundation increased. When the contact angle was 135°, as in case A1 in this study, 4.1 tons and 3.4 tons were measured at the sockets and pipe body, respectively. For a contact angle of 90° (case A2), the destructive strength was measured as 3.7 tons at the sockets and 2.9 tons at the pipe body. Overall, the deformation of the pipe resulted in tensile strain in the diametrical direction, and slight shrinkage occurred in the longitudinal direction of the pipe as a result of loading on a prefabricated lightweight plastic foundation. For the foundation of the polyethylene triple-wall corrugated pipe, 100 % new plastic was used for case B1, whereas 50 % recycled plastic was used for case B2. The results show that 1.49 tons were observed at 5 % of pipe strain for case B1, whereas 1.35 tons were observed at 5 % of pipe strain for case B2. The recycled plastic foundation showed a tendency to somewhat reduce the load relative to the foundation that consisted of original materials. The results of destructive strength tests on a plastic foundation show that case B1 featured 13.78 tons of loading and 5.16 mm of deformation, whereas case B2 showed 9.66 tons of loading and 5.41 mm of deformation.

탄두 충돌 시 기폭관 컵의 변형 해석

In this paper, we have investigated deformation of cup for EFI detonator in high velocity impact test. The experimental result shows that STS cup deformed 0.170 mm with the bulged shape. The numerical simulation result with static/dynamic material properties of SUS304 shows 0.166 mm of deformation. The main parameters to decrease the deformation of cup are stength, thickness and density of cup. The initial condition of SUS304 cup was strength of 215 MPa and thickness of 0.12 mm. As strength increases to 500 MPa, deformation of cup converges to 0 mm, and as thickness increases to 0.18 mm, deformation of cup converges to 0 mm. If the density of cup decreases from 8 to 2.7 g/cc, the deformation of cup decreases to 0.141 mm.

SU‐GG‐J‐195: Utility of a Calibrated Deformation Map to Aid Treatment Position and Monitoring Guidance in Deforming Anatomy with Electromagnetic Transponders

Purpose: To investigate the utility of tracking motion and deformation in various regions of a deforming geometry given a predetermined “calibrated” deformation map and relative position of a small number of embedded electromagnetic transponders. Method and Materials: Three electromagnetic transponders were inserted into a reproducibly deformable phantom and localized with CT. Tumor‐simulating spheres were embedded at different positions relative to the transponders. The phantom was imaged at 7 compression (“breathing”) states, and the transponders and tumors were localized on each image volume. Deformation maps relating a reference (end inhalation) to all other states were estimated using a B‐spline based registration technique. Principal component analysis was applied to the deformation maps to find the most significant modes of deformation in the phantom. This created a calibration state for the deformation which can be used along with the measured transponder positions to estimate the deformation at arbitrary time point during a breathing cycle. Results: Tests performed based on information from one transponder showed variable uncertainty (8 mm) in predicting arbitrary target positions at different states during a breathing cycle. Application of all three transponders to the first component of deformation showed very high accuracy with a mean error of less than 1mm for deformation maps calibrated on 5 breathing states. Using only the 2 extremes of the breathing cycle, the mean error increased to 2mm, showing some dependence on the number of states used in calibration of the deformation map. Extrapolation of the breathing state past the calibration data by an additional 1cm of compression showed reasonable accuracy (3.5 mm). Conclusion: A calibrated deformation map can potentially be used as an aid to dynamic tracking of deforming anatomy during treatment. Experiments are ongoing to evaluate the dynamic behavior of the calibrated maps to real‐time data from the tracking system. Supported by NIHP01CA59827.

Extreme deformation and damage during the construction of large tunnels

Extreme deformations occurred during the construction both prior to and through a significant fault zone along the 16-m-wide. three-lane, twin tubes of the Bolu Mountain Tunnel of the 114 km Anatolian Motorway in north-central Turkey. Semi-concurrent excavation of the full top benches of both large tunnels was carried out through the fault zone with a final design deformation tolerance of 500mm in accordance with a NATM design philosophy. During excavation maximum deformations in the left and right tubes reached 580 mm and 350 mm, respectively. With continued semi-concurrent excavation through the fault zone an additional 140 mm of deformation occurred in the left tube thus, greatly exceeding the design tolerance. Extensive damage of the installed tunnel supports in the form of cracked shotcrete and distorted steel arches was observed in both tubes. An investigation was carried out on behalf of re-insurers to assess the causes of the additional deformation that exceeded the design tolerance. The main cause of the additional deformation aabove the design tolerance has been attributed to the re-start of excavation of the large lower benches of both tubes and the significant stress re-distribution that occurs with this excavation stage for large tunnels sited in weak geological conditions. This paper presents the summary findings of the review of the investigation that was carried out for re-insurers of the project as to the causes of the additional deformation that exceeded the design tolerance.

A biomechanical study of Jefferson fractures.

Fifteen specimens of the first cervical vertebra were tested by the application of pure tensile forces to failure. Seven specimens had intact transverse ligaments, and eight had transection of the transverse ligament before testing. Specimens were tested to failure by the rapid application of laterally directed tensile force to the ring; this force then was exerted through the lateral masses to simulate the mechanism of injury for this fracture as proposed by Jefferson. To measure the biomechanical characteristics of the C1 ring, including the fracture patterns created with tensile loading, and to describe the influence of the transverse ligament on the behavior of the ring as it failed under tension. Jefferson fractures have been reproduced in the laboratory by subjecting head and neck preparations to axial load. However, no previous detailed biomechanical studies of the fracture characteristics of the isolated C1 vertebra have been reported. Specimens were tested to failure by rapid application of laterally directed tensile forces to the ring. Eleven two-part and three three-part fractures occurred. The mean tensile strength of the atlas was found to be 2,280 N. The average deformation required to fracture the C1 ring was 1.57 mm. The total energy absorbed by the ring averaged 1.99 N-m. There was no statistically difference between those specimens with the transverse ligament intact and those without a transverse ligament. The results of this study show that fractures of the C1 ring of greater than two parts can occur with pure tensile loading. The ring will fracture with as little as 1 mm of deformation.