scholarly journals Comparison of Test Setups for the Experimental Evaluation of the Primary Fixation Stability of Acetabular Cups

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3982
Author(s):  
Christian Schulze ◽  
Danny Vogel ◽  
Sina Mallow ◽  
Rainer Bader
Keyword(s):  
Test Methods ◽  
Load Test ◽  
Test Method ◽  
Artificial Bone ◽  
Acetabular Cup ◽  
Acetabular Bone ◽  
Press Fit ◽  
Orthopedic Surgeons ◽  
Fixation Stability

Sufficient primary fixation stability is the basis for the osseointegration of cementless acetabular cups. Several test methods have been established for determining the tilting moment of acetabular press-fit cups, which is a measure for their primary fixation stability. The central aim of this experimental study was to show the differences between the commonly used lever-out test method (Method 1) and the edge-load test method (Method 2) in which the cup insert is axially loaded (1 kN) during the tilting process with respect to the parameters, tilting moment, and interface stiffness. Therefore, using a biomechanical cup block model, a press-fit cup design with a macro-structured surface was pushed into three cavity types (intact, moderate superior defect, and two-point-pinching cavity) made of 15 pcf and 30 pcf polyurethane foam blocks (n = 3 per cavity and foam density combination), respectively. Subsequently, the acetabular cup was disassembled from the three artificial bone cavities using the lever-out and the edge-load test method. Tilting moments determined with Method 1 ranged from 2.72 ± 0.29 Nm to 49.08 ± 1.50 Nm, and with Method 2, they ranged from 41.40 ± 1.05 Nm to 112.86 ± 5.29 Nm. In Method 2, larger areas of abrasion were observed in the artificial bone cavity compared to Method 1. This indicates increased shear forces at the implant–bone interface in the former method. In conclusion, Method 1 simulates the technique used by orthopedic surgeons to assess the correct fit of the trial cup, while Method 2 simulates the tilting of the cup in the acetabular bone cavity under in situ loading with the hip resultant force.

In situ testing and its application to foundation engineering

1986 ◽  
Vol 23 (4) ◽  
pp. 573-594 ◽  
Author(s):  
P. K. Robertson
Keyword(s):  
Test Methods ◽  
Load Test ◽  
Foundation Engineering ◽  
Penetration Test ◽  
In Situ Testing ◽  
Cone Penetration ◽  
Specific Test ◽  
Pressuremeter Test ◽  
In Situ Test

The status of in situ testing and its application to foundation engineering are presented and discussed. The in situ test methods are discussed within the framework of three groups: logging, specific, and combined test methods. The major logging test methods discussed are standard penetration test (SPT), cone penetration test (CPT), and the flat plate dilatometer test (DMT). The major specific test methods discussed are the prebored pressuremeter test (PMT), the self-bored pressuremeter test (SBPMT), and the screw plate load test (SPLT). Discussion is also presented on recent tests that combine features of logging tests (using the CPT) and specific tests (e.g. the seismic, the electrical resistivity/dielectric, and the lateral stress sensing cone penetration tests). A brief discussion is also presented on the applicability, as perceived by the author, of existing in situ test methods and the future of in situ testing applied to foundation engineering. Key words: in situ testing, foundation engineering, penetration testing, pressuremeter.

scholarly journals What can gaze behaviors, neuroimaging data, and test scores tell us about test method effects and cognitive load in listening assessments?

2021 ◽  
pp. 026553222110268
Author(s):  
Vahid Aryadoust ◽  
Stacy Foo ◽  
Li Ying Ng
Keyword(s):  
Eye Tracking ◽  
Cognitive Load ◽  
Test Scores ◽  
Test Validity ◽  
Test Methods ◽  
Load Test ◽  
Test Method ◽  
Functional Near Infrared Spectroscopy ◽  
Listening Test ◽  
The Impact

The aim of this study was to investigate how test methods affect listening test takers’ performance and cognitive load. Test methods were defined and operationalized as while-listening performance (WLP) and post-listening performance (PLP) formats. To achieve the goal of the study, we examined test takers’ ( N = 80) brain activity patterns (measured by functional near-infrared spectroscopy (fNIRS)), gaze behaviors (measured by eye-tracking), and listening performance (measured by test scores) across the two test methods. We found that the test takers displayed lower activity levels across brain regions supporting comprehension during the WLP tests relative to the PLP tests. Additionally, the gaze behavioral patterns exhibited during the WLP tests suggested that the test takers adopted keyword matching and “shallow listening.” Together, the neuroimaging and gaze behavioral data indicated that the WLP tests imposed a lower cognitive load on the test takers than the PLP tests. However, the test takers performed better with higher test scores for one of two WLP tests compared with the PLP tests. By incorporating eye-tracking and neuroimaging in this exploration, this study has advanced the current knowledge on cognitive load and the impact imposed by different listening test methods. To advance our knowledge of test validity, other researchers could adopt our research protocol and focus on extending the test method framework used in this study.

Theoretical Model for Calculating the Rotation in Cementless Acetabular Cup Prosthesis Implanted by Press Fit into a Hip of Canines

2014 ◽  
Vol 627 ◽  
pp. 101-104
Author(s):  
Ruben Lostado Lorza ◽  
William T. McCartney ◽  
Bryan J. Mac Donald ◽  
Roberto Fernandez Martinez
Keyword(s):  
Theoretical Model ◽  
Aseptic Loosening ◽  
Surgical Intervention ◽  
Static Friction ◽  
Maximum Load ◽  
Artificial Bone ◽  
Acetabular Cup ◽  
Press Fit ◽  
Excessive Load ◽  
Net Load

The aseptic loosening of the cementless acetabular cup prosthesis implanted by press fit into a hip is a fault caused by the application of an excessive load, which creates the rotation of the cup on the hip [1]. This rotation of the cup on the hip disables the prosthesis, and a new surgical intervention to place correctly the cup in the hip housing is required. The aseptic loosening of the cementless acetabular cup has been studied during decades mainly through experiments and numerical methods [2,3,4]. This paper shows the development of a theoretical model for calculating the maximum load that the cup of the prosthesis can support as well as the angle and direction of the net load. The model proposed is based on the hertz laws [5], which considers the interface between the cup and hip as two spheres between which there is a coefficient of static friction (μ), and is applied on a acetabular cups [6] implanted in artificial bone [7].

scholarly journals Reinforcement and Restoration Studies of the Edremit Ataturk House

2020 ◽  
Vol 10 (2) ◽  
pp. 5346-5351
Author(s):  
B. M. Bagbanci
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Properties ◽  
Element Model ◽  
Test Methods ◽  
Test Method ◽  
Before And After ◽  
Vibration Tests ◽  
Non Destructive

Edremit Ataturk House has been restored under international restoration principles. Due to its importance, a systematic study was carried out to prevent the building from suffering damage. The current situation of the building was investigated by using slightly destructive and non-destructive test methods. Flat-jack and shear tests were used in order to identify the mechanical properties of masonry walls according to the ASTM standards. The operational modal analysis test method was used in order to understand its dynamic characteristics. After the diagnosis phase, a finite element model was prepared and calibrated according to the in-situ test results. The reinforcement studies were performed according to the finite element modal analysis results. Finally, the differences between the dynamic properties of the structure were evaluated by vibration tests before and after the restoration works.

Point-Load Test Method for Estimation of In Situ Masonry Mortar Strength

2020 ◽  
Vol 32 (10) ◽  
pp. 04020286
Author(s):  
Suhang Yang ◽  
Junwen Zhou ◽  
Zhengning Bian ◽  
Zhifeng Xu
Keyword(s):  
Point Load ◽  
Load Test ◽  
Test Method ◽  
Point Load Test ◽  
Mortar Strength ◽  
Masonry Mortar

Test Method Development to Quantify the In Situ Elastic and Plastic Behavior of 62%Sn–36%Pb–2%Ag Solder Ball Arrays in Commercial Area Array Packages at −40 °C , 23 °C, and 125 °C

2005 ◽  
Vol 127 (4) ◽  
pp. 483-495 ◽  
Author(s):  
Ahmad Abu Obaid ◽  
Jay G. Sloan ◽  
Mark A. Lamontia ◽  
Antonio Paesano ◽  
Subhotosh Khan ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Solder Ball ◽  
Method Development ◽  
Failure Modes ◽  
Test Methods ◽  
Shear Loading ◽  
Test Method ◽  
Plastic Behavior ◽  
Area Array

The objective of this study is to describe and evaluate test methods developed to experimentally characterize the in situ mechanical behavior of solder ball arrays connecting printed wiring boards to area array packages under tensile, compressive, and shear loading at −40, 23, and 125 °C. The solder ball arrays tested were composed of 62%Sn–36%Pb–2%Ag solder alloy. Finite element modeling was performed. The results indicated that the test fixture should be geometrically equivalent to the projected shape of the ball grid array to achieve uniform loading. Tension, compression, and shear tests were conducted. For tensile loading the interfaces and the solder balls are loaded in series resulting in a large apparent strain (13%). Various interfacial failure modes are observed. Under compression and shear loading the effect of the interfaces are negligible and therefore a significant deformation and a remarkable yielding behavior of solder ball arrays can be observed. Furthermore, the specimens tested under shear loading showed different failure modes such as cohesive or adhesive failure modes depending on the test temperature. From the overall results, it has been determined that shear loading is the most representative test to measure the actual mechanical behavior of solder in ball grid arrays.

scholarly journals Research on Test Method of Foundation Bed Coefficient in Nanjing Soft Soil Area

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Min Zhang ◽  
Tao Qiu
Keyword(s):  
Soft Soil ◽  
Test Methods ◽  
Test Method ◽  
Test Results ◽  
Research Findings ◽  
Engineering Survey ◽  
Soft Soil Area ◽  
Soil Foundation ◽  
Soil Area

Relying on the geotechnical engineering survey project of Nanjing Lukou Airport, this research adopts the method of combining in situ and indoor testing to analyze the coefficient of soil foundation under different conditions (flow plastic, plastic, and soft plastic). Based on the differences in test results, in situ and indoor test methods appropriate for the benchmark bed coefficient of Nanjing soft soil area are proposed. Research findings depicted that the bed coefficients obtained by different methods are not similar; therefore, if the data obtained by different methods need to be compared and analyzed, they have to be unified as K 30 . Simultaneously, in the indoor test, this study compared the foundation bed coefficient obtained by the consolidation method, the improved K 0 instrument consolidation method, and the triaxial method. Results revealed that the improved K 0 instrument consolidation method can better realize the test of the soil foundation coefficient. This study can provide a reference for geotechnical investigation and design of soft soil in the study area.

scholarly journals Backside Wear Analysis of Retrieved Acetabular Liners with a Press-Fit Locking Mechanism in Comparison to Wear Simulation In Vitro

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Ana Laura Puente Reyna ◽  
Marcus Jäger ◽  
Thilo Floerkemeier ◽  
Sven Frecher ◽  
Karl-Stefan Delank ◽  
...  
Keyword(s):  
Acetabular Cup ◽  
Wear Process ◽  
Press Fit ◽  
Locking Mechanism ◽  
Inner Surface ◽  
Backside Wear ◽  
And Behavior ◽  
Wear Modes

Backside wear due to micromotion and poor conformity between the liner and its titanium alloy shell may contribute to the high rates of retroacetabular osteolysis and consequent aseptic loosening. The purpose of our study was to understand the wear process on the backside of polyethylene liners from two acetabular cup systems, whose locking mechanism is based on a press-fit cone in combination with a rough titanium conical inner surface on the fixation area. A direct comparison between in vitro wear simulator tests (equivalent to 3 years of use) and retrieved liners (average 13.1 months in situ) was done in order to evaluate the backside wear characteristics and behavior of these systems. Similar wear scores between in vitro tested and retrieved liners were observed. The results showed that this locking mechanism did not significantly produce wear marks at the backside of the polyethylene liners due to micromotion. In all the analyzed liners, the most common wear modes observed were small scratches at the cranial fixation zone directly below the rough titanium inner surface of the shell. It was concluded that most of the wear marks were produced during the insertion and removal of the liner, rather than during its time in situ.

Ice Shear Adhesion Test Methods Review and New In Situ Test Method

2021 ◽  
Author(s):  
Edem Y. Tetteh ◽  
Michael W. Jeong ◽  
Eric Loth
Keyword(s):  
Test Methods ◽  
Test Method ◽  
Adhesion Test ◽  
In Situ Test

The Test Analysis of the Bearing Capacity of Foundation

2014 ◽  
Vol 962-965 ◽  
pp. 357-360
Author(s):  
Ya Jun Yin ◽  
Xue Wen Xie ◽  
Yong Mei Qian
Keyword(s):  
Bearing Capacity ◽  
Standard Penetration Test ◽  
Test Methods ◽  
Test Point ◽  
Load Test ◽  
Test Method ◽  
Penetration Test ◽  
Loading Test ◽  
Test Analysis ◽  
Foundation Soil

The test method of shallow plate load was used in the bearing capacity of foundation of Yushu City , doing two groups of loading test in different depths and doing survey and comparative test between test point nearby and sites in the same horizon.It gets the law of foundation soil bearing capacity value got by different test methods and provides the basis for Jilin Province to establish the local standards through the comparison of load test and geotechnical test , static cone penetration test and standard penetration test.

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