Combat helmet liner design for blunt impact absorption using multi-output Gaussian process surrogates

2020 ◽  
pp. 095440622096076 ◽  
Author(s):  
George J Barlow ◽  
Christopher Page ◽  
Patrick Drane ◽  
Scott E Stapleton ◽  
Benjamin Fasel ◽  
...  
Keyword(s):  
Gaussian Process ◽  
Impact Velocity ◽  
Linear Acceleration ◽  
Design Parameters ◽  
Test Results ◽  
Design Metrics ◽  
Impact Performance ◽  
Blunt Impact ◽  
Testing Standards ◽  
First Time

A finite element based computational model simulating the standard drop tower test for military helmets was created and used in conjunction with a multi-output Gaussian process surrogate to seek different designs of helmets for improved blunt impact performance. Experimental drop test results were used for the validation of the model’s ability to simulate impact. The influence of foam stiffness, impact velocity, strap tension, as well as pad placement and size on parameters on the peak linear acceleration (PLA) of the headform was investigated for the first time through a surrogate model trained by strategically choosing simulation points. Impact velocity was found to have the greatest effect. The strap tension and foam pad stiffness ranges examined within this sampling plan were found to have less of an effect on the performance of the helmet than the pad size and shape parameters examined. The surrogate modeling approach was used to quantify the influence of design parameters and can lead to not only improved helmet designs but also new data-driven design metrics and testing standards to accelerate the development of TBI-mitigating helmets.

Differences in Impact Performance of Bicycle Helmets During Oblique Impacts

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Megan L. Bland ◽  
Craig McNally ◽  
Steven Rowson
Keyword(s):  
Real World ◽  
Head Injuries ◽  
Linear Acceleration ◽  
Design Parameters ◽  
Radius Of Curvature ◽  
Head Impacts ◽  
Impact Performance ◽  
Bicycle Helmets ◽  
Oblique Impacts ◽  
Accident Conditions

Cycling is a leading cause of sport-related head injuries in the U.S. Although bicycle helmets must comply with standards limiting head acceleration in severe impacts, helmets are not evaluated under more common, concussive-level impacts, and limited data are available indicating which helmets offer superior protection. Further, standards evaluate normal impacts, while real-world cyclist head impacts are oblique—involving normal and tangential velocities. The objective of this study was to investigate differences in protective capabilities of ten helmet models under common real-world accident conditions. Oblique impacts were evaluated through drop tests onto an angled anvil at common cyclist head impact velocities and locations. Linear and rotational accelerations were evaluated and related to concussion risk, which was then correlated with design parameters. Significant differences were observed in linear and rotational accelerations between models, producing concussion risks spanning >50% within single impact configurations. Risk differences were more attributable to linear acceleration, as rotational varied less between models. At the temporal location, shell thickness, vent configuration, and radius of curvature were found to influence helmet effective stiffness. This should be optimized to reduce impact kinematics. At the frontal, helmet rim location, liner thickness tapered off for some helmets, likely due to lack of standards testing at this location. This is a frequently impacted location for cyclists, suggesting that the standards testable area should be expanded to include the rim. These results can inform manufacturers, standards bodies, and consumers alike, aiding the development of improved bicycle helmet safety.

scholarly journals COT-13 Current situation and problems of cancer genomic profiling test in Kyoto University Hospital

2020 ◽  
Vol 2 (Supplement_3) ◽  
pp. ii22-ii22
Author(s):  
Yoshiki Arakawa ◽  
Junko Suga ◽  
Yukinori Terada ◽  
Kohei Nakajima ◽  
Masahiro Tanji ◽  
...  
Keyword(s):  
Treatment Options ◽  
Insurance Coverage ◽  
Germline Mutations ◽  
University Hospital ◽  
Genomic Profiling ◽  
Test Results ◽  
Final Test ◽  
First Time ◽  
To Receive ◽  
Secondary Finding

Abstract Objective: Kyoto University Hospital has introduced the cancer genomic profiling tests, Oncoprime in 2015, Guardant360 in 2018, which are not under insurance coverage, FoundationOne CDx(F1CDx) and OncoGuide NCC Oncopanel system(NCC OP) in 2019, which received approval for insurance coverage for the first time in Japan. We investigated the results of cancer genomic profiling test under insurance coverage in our hospital. Methods: A special facility for the cancer genomic profiling tests was produced. To perform the cancer genomic profiling test, an outpatient must visit the facility three times (learning, ordering of the test, and getting the results). The expert panels decide the final test results and treatment options with the all information of the patients. Results: From November 2019 to March 2020, 51 and 9 patients were tested with F1CDx and NCC OP, respectively. 16 patients (31%) of F1CDX and 2 patients (22%) of NCC OP got treatment recommendations from the expert panels. However, only 5 patients (9.8%) of F1CDX and 1 patient (11%) of NCC OP received the treatments. The secondary finding suspecting germline mutations was found in 8 patients of F1CDX. Conclusion: After the approval the cancer genomic profiling tests with insurance coverage in Japan, it becomes easy for the patients to perform the test and get the genetic information of the tumor. However, it remains not easy to receive the recommended drugs because of several limitations of their usages.

Improving the Strength of Abrasive Wheels and Optimizing the Control over the Strength of Composite Abrasive Materials

2019 ◽  
Vol 946 ◽  
pp. 380-385
Author(s):  
Boris A. Chaplygin ◽  
Viacheslav V. Shirokov ◽  
Tat'yana A. Lisovskaya ◽  
Roman A. Lisovskiy
Keyword(s):  
Mechanical Properties ◽  
Test Results ◽  
Key Factors ◽  
Special Equipment ◽  
Material Density ◽  
Factors Affecting ◽  
Control Factors ◽  
Reinforcing Material ◽  
Special Studies ◽  
First Time

The strength of abrasive wheels is one of the key factors affecting the performance of abrasive machining. The paper discusses ways to improve the strength of abrasive wheels. The stress-state mathematical model presented herein is a generalization of the existing models. It is used herein to find for the first time that there are numerous optimal combinations of the elastic modulus and reinforcing material density, which result in the same minimum value of the objective function. It is found out that increasing the radius of the reinforcing component while also optimizing the mechanical properties of its material may increase the permissible breaking speed of the wheel several times. We herein present a regression equation and a nomogram for finding the optimal combination of control factors. Conventional methods for testing the mechanical properties of materials, which have been proven reliable for testing metals and alloys, are not as reliable for testing abrasive materials, as the test results they generate are not sufficiently stable or accurate. We therefore propose an alternative method that does not require any special equipment or special studies.

scholarly journals Kaolin based protective barrier in municipal landfills against adverse chemo-mechanical loadings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Partha Das ◽  
Tadikonda Venkata Bharat
Keyword(s):  
Ionic Strength ◽  
High Ionic Strength ◽  
The Self ◽  
Design Parameters ◽  
Layered System ◽  
Geosynthetic Clay Liners ◽  
Clay Liners ◽  
Landfill Liner ◽  
First Time ◽  
Applied Stresses

AbstractIn this work, we assess the self-sealing and swelling ability of the compacted granular bentonite (GB) under an inorganic salt environment and induced overburden stresses from the landfill waste. The laboratory permeation tests with high ionic strength salt solutions reveal that the GB fails to seal and exhibits a significant mechanical collapse under different applied stresses. The applicability of GB in the form of geosynthetic clay liners as the bottom liner facilities in landfills that produce high ionic strength salt leachates, therefore, remains a serious concern. We propose an additional barrier system based on kaolin, for the first time, to address this problem. The proposed kaolin-GB layered system performs satisfactorily in terms of its sealing and swelling ability even in adverse saline conditions and low overburden stresses. The kaolin improves the osmotic efficiency of the self and also helps the underlying GB layer to seal the inter-granular voids. The estimated design parameters by through-diffusion test suggest that the kaolin-GB layered system effectively attenuates the permeant flux and suitable as a landfill liner.

Estimation of Seismic Energy Dissipation for Steel Slit Shear Walls Considering Out-of-Plane Buckling

2021 ◽  
Author(s):  
Yiming Ma ◽  
Liusheng He ◽  
Ming Li
Keyword(s):  
Energy Dissipation ◽  
Shear Walls ◽  
Seismic Energy ◽  
Thickness Ratio ◽  
Design Parameters ◽  
Test Results ◽  
Loading Test ◽  
Aspect Ratios ◽  
Out Of Plane ◽  
Energy Dissipation Capacity

Steel slit shear walls (SSSWs), made by cutting slits in steel plates, are increasingly adopted in seismic design of buildings for energy dissipation. This paper estimates the seismic energy dissipation capacity of SSSWs considering out-of-plane buckling. In the experimental study, three SSSW specimens were designed with different width-thickness ratios and aspect ratios and tested under quasi-static cyclic loading. Test results showed that the width-thickness ratio of the links dominated the occurrence of out-of-plane buckling, which produced pinching in the hysteresis and thus reduced the energy dissipation capacity. Out-of-plane buckling occurred earlier for the links with a larger width-thickness ratio, and vice versa. Refined finite element model was built for the SSSW specimens, and validated by the test results. The concept of average pinching parameter was proposed to quantify the degree of pinching in the hysteresis. Through the parametric analysis, an equation was derived to estimate the average pinching parameter of the SSSWs with different design parameters. A new method for estimating the energy dissipation of the SSSWs considering out-of-plane buckling was proposed, by which the predicted energy dissipation agreed well with the test results.

Ambient vibration test results of the Imperial County Services Building

1983 ◽  
Vol 73 (6A) ◽  
pp. 1895-1902
Author(s):  
Gerard C. Pardoen
Keyword(s):  
Strong Motion ◽  
Ambient Vibration ◽  
Vibration Test ◽  
Test Results ◽  
Structural Failure ◽  
Imperial Valley ◽  
Ambient Vibration Test ◽  
Significant Interest ◽  
First Time ◽  
County Services

Abstract The ambient vibration test results conducted on the Imperial County Services Building prior to the 15 October 1979 Imperial Valley earthquake are summarized. These results are of significant interest because the Imperial County Services Building has been the source of many postearthquake investigations due to the fact that the 1979 earthquake represented the first time a building instrumented with strong motion recorders suffered and recorded the major structural failure.

Answering the Questions of the Psychologist Assessing the Visually Handicapped Child

1975 ◽  
Vol 69 (8) ◽  
pp. 350-353
Author(s):  
John L. Morse
Keyword(s):  
Classroom Observation ◽  
Handicapped Child ◽  
Test Results ◽  
Visual Condition ◽  
Inappropriate Behaviors ◽  
Test Conditions ◽  
Visually Handicapped ◽  
First Time

The most common question asked by the psychologist who is faced for the first time with assessing a visually handicapped child are answered. The 15 questions include such areas as the required information concerning visual condition, background of the client, test conditions, the role of the parents, classroom observation, behaviors observed during testing, evaluation of test results, expectations of parents and teachers, and modification of a child's inappropriate behaviors.

Design of Six Freedom Vibration Acquisition System for Military Vehicle

2012 ◽  
Vol 430-432 ◽  
pp. 1866-1870
Author(s):  
Zhi Xiong Zhu ◽  
Shi Shun Zhu ◽  
Guo Jun Wang ◽  
Yan Zhu
Keyword(s):  
Reference System ◽  
Vibration Spectrum ◽  
Object Oriented ◽  
Linear Acceleration ◽  
Test Results ◽  
Collection System ◽  
Analysis And Design ◽  
Design And Implementation ◽  
Military Vehicle ◽  
Collection Data

Design and implementation of six freedom transportation vibration spectrum collection system is presented in this paper. The Attitude and Heading Reference System (AHRS) is used to capture signals including x, y, z, direction linear acceleration, angular rates around Z-axis and pitch, roll degree. The software’s architecture and modules for host computer is designed with object-oriented analysis and design techniques, and the software is implemented with VC++6.0. The test results show that the system was able to collect vehicular vibration information on time and the collection data was replayed on the vibration platform.

Optimization of Radiation Shielding Concrete for Radiotherapy Treatment Room at Bangabandhu Sheikh Mujib Medical University

2016 ◽  
Vol 705 ◽  
pp. 338-344
Author(s):  
Debojit Sarker ◽  
Arnab Biswas ◽  
Md. Mizanur Rahman ◽  
Muhammad Mohsin Mehedi
Keyword(s):  
Side Wall ◽  
Linear Acceleration ◽  
Radiation Shielding ◽  
Design Parameters ◽  
Slab Thickness ◽  
Optimized Design ◽  
The Public ◽  
Dose Limits ◽  
Medical University ◽  
Shield Design

The objective of this study is to recommend optimized shield design from the shielding viewpoint for installation of the Cyclotron,Cyberknife and Linear Acceleration (LINAC) facility at Bangabandhu Sheikh Mujib Medical University (BSMMU) in Dhaka, Bangladesh. The shield design for Cyclotron, Cyberknife and LINAC has been performed considering ICRP-103 (2007) recommendations for occupational and public dose limits. The optimized design parameters for Radiation Shielding Concrete (RSC) with hardened density of 2.35 gm/cm3 are: 254 cm thickness of RSC as primary barrier for LINAC on both side of the source, 198 cm and 178 cm thickness of RSC on parking side and earthen side wall for Cyclotron, a maze wall of thickness 198 cm and 122 cmRSC for Cyclotron and LINAC, 168 cm and 152 cm thickness of RSC from opposite to the maze wall, slab thickness 152 cm excluding a false ceiling of thickness 122 cm with RSC having a functional story height of 503 cm for LINAC, 122 cm and 259 cm slab thickness of RSC for Cyberknife and Cyclotron. The use of RSC in the shield design of wall and roof shows that it limits radiation exposure of staff, patients, visitors and the public to acceptable level, thus optimizing radiation protection.

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