The Experts below are selected from a list of 109200 Experts worldwide ranked by ideXlab platform
Astrid Linder - One of the best experts on this subject based on the ideXlab platform.
-
average male and female virtual dummy model biorid and evarid simulations with two seat concepts in the euro ncap low severity rear impact Test Configuration
Accident Analysis & Prevention, 2017Co-Authors: Astrid Linder, Kristian Holmqvist, Mats Y SvenssonAbstract:Soft tissue neck injuries, also referred to as whiplash injuries, which can lead to long term suffering accounts for more than 60% of the cost of all injuries leading to permanent medical impairmen ...
-
simulations with average male and female dummy models with two seat concepts in the euro ncap low severity rear impact Test Configuration
17th International Conference Road Safety On Five Continents (RS5C 2016) Rio de Janeiro Brazil 17-19 May 2016, 2016Co-Authors: Astrid Linder, Kristian Holmqvist, Mats Y SvenssonAbstract:Soft tissue neck injuries, also referred to as whiplash injuries, which can lead to long term suffering are most common in rear impacts. These injuries account for more than 60% of the cost of all injuries leading to permanent medical impairment for the insurance companies with respect to injuries sustained in vehicle crashes. Injury statistics have since the mid-1960s consistently shown that females are subject to a higher risk of sustaining this type of injury than males, on average twice the risk of injury. Furthermore, recently developed anti-whiplash systems have shown to protect females less than males. The diversity of males and females should be addresses when designing and evaluating vehicle safety systems to ensure maximum safety for everyone. This is currently not the case. The norm for crash Test dummies representing humans in crash Test laboratories is an average male. The female part of the population is not represented in Tests performed by consumer information organisations such as NCAP due to the absence of a physical dummy representing an average female. Recently, the world first virtual model of an average female crash Test dummy was developed. In this study, simulations were run with both an average male, and the recently developed average female dummy model, seated in a laboratory vehicle seat. The results of the simulations were compared to earlier published results from the same Test set-up with a vehicle concepts seat. The three crash pulse severities of the Euro NCAP low severity rear impact Test were applied. The motion of the neck, head and upper torso were analysed in addition to the accelerations and the Neck Injury Criterion (NIC). Furthermore, the response of the virtual models was compared to that volunteers and for the average male model, to that of the response of a physical dummy model. Simulations with the male and the female dummy models revealed differences related to the crash severity, as well as between the two dummies in different crash severities in two different seats. For the comparison of the response of the virtual models to the response of the volunteers and the physical dummy model, the peak angular motion of first thoracic vertebra as found in the volunteer Tests and mimicked by the physical dummy were not of the same magnitude in the virtual models.
M R M Aliha - One of the best experts on this subject based on the ideXlab platform.
-
Mixed Mode I/II Fracture Analysis of Bi-Material Adhesive Bonded Joints Using a Novel Short Beam Specimen
'MDPI AG', 2021Co-Authors: M R M Aliha, Hadi Ghesmati Kucheki, Mirmilad MirsayarAbstract:Until now, some Test specimens with different shapes and loading mechanisms have been utilized for investigating the cracking behavior of adhesive bounded joints. In this research, using a novel Test Configuration called adhesive short bend beam specimen containing an inclined crack and loaded by three-point bending, mixed mode I/II fracture parameters of a crack initiated in the adhesive part is studied. Compared to other Test methods, the specimen used in this research needs a lesser amount of material and the fracture Test can be performed easily. A large number of finite element models of this specimen were analyzed using ABAQUS code to study the effect of adhesive and adherent type, and also the crack length and loading span distance on KI, KII, T-stress and fracture initiation direction under different mode mixities. The results showed that the fracture parameters (and in particular the shear mode component) are sensitive to the type and location of adherent in the bounded joint; however, the shape and size of fracture plastic zone is not affected noticeably by the type of adhesive-adherent materials. It was also shown that the complete mode mixities ranging from pure mode I to pure mode II can be introduced for adhesive bounded joints using the proposed Test specimen and therefore the specimen is a good candidate Test Configuration for investigating the mixed mode I/II fracture behavior of adhesive bounded joints
-
fracture assessment of polymethyl methacrylate using sharp notched disc bend specimens under mixed mode i iii loading
Physical Mesomechanics, 2016Co-Authors: M R M Aliha, Filippo Berto, A Bahmani, Sh Akhondi, Afrooz BarnoushAbstract:Mixed mode I/III behavior of Perspex (polymethyl methacrylate (PMMA)) is studied experimentally and theoretically in this research using a new and simple laboratory Test Configuration. The specimen is a circular disc containing a sharp V-notch along the diameter that is loaded by the conventional three-point bend fixture. The critical values of notch stress intensity factors (KIV and KIIIV) were obtained for the whole combinations of modes I and III simply by changing the notch inclination angle relative to the loading rollers. The value of notch fracture toughness under pure or dominantly tension loads was greater than its corresponding value under mode III or dominantly torsion loads. The experimental results were also predicted very well by employing the local strain energy density (SED) criterion.
-
determination of mode iii fracture toughness for different materials using a new designed Test Configuration
Materials & Design, 2015Co-Authors: M R M Aliha, A Bahmani, Sh AkhondiAbstract:Abstract In practical applications it is important to determine resistance of cracked materials against out of plane sliding deformation (i.e. mode III fracture toughness (KIIIc)) using suitable Testing methods. However, lack of a suitable Test Configuration for obtaining KIIIc is still one of the shortcomings in fracture mechanics. In this paper, a simple specimen called Edge Notched Disc Bend (ENDB) is proposed for experimental determination of KIIIc. This specimen is a circular disc containing an edge crack created along the disc diameter which is subjected to three-point bend loading. Both pure modes I and III loading conditions can be easily achieved by the ENDB specimen by choosing the crack orientation in appropriate direction relative to the applied loading. In order to examine the practical ability of the suggested specimen a number of ENDB specimens made of different materials including PMMA, asphalt concrete, graphite and a marble rock are Tested under both modes I and III. It is also observed that for each material the mode III fracture toughness is less than the corresponding mode I fracture toughness value. The obtained fracture toughness ratio KIIIc/KIc for the Tested materials is also predicted theoretically using a strain energy based criterion.
-
numerical analysis of a new mixed mode i iii fracture Test specimen
Engineering Fracture Mechanics, 2015Co-Authors: M R M Aliha, A Bahmani, Sh AkhondiAbstract:Abstract A new Test Configuration called the edge notched disc bend specimen is suggested for investigating mixed mode I/III fracture behavior. The proposed specimen is a circular disc containing an inclined edge crack thorough the diameter and is subjected to three point bend loading. Extensive three dimensional finite element analyses were performed for different geometrical parameters and loading conditions to obtain the stress intensity factors and the T-stress in the proposed disc bend specimen. The finite element results showed that the suggested specimen is able to introduce full combinations of mixed mode I/III ranging from pure mode I to pure mode III.
-
analysis of a new specimen for mixed mode fracture Tests on brittle materials
Engineering Fracture Mechanics, 2009Co-Authors: M R Ayatollahi, M R M AlihaAbstract:Numerical and experimental studies were performed on a new fracture Test Configuration called the diagonally loaded square plate (DLSP) specimen. The mode I and mode II stress intensity factors were computed for different crack lengths and crack orientation angles using finite element analysis. The numerical results show that the DLSP specimen is able to provide pure mode I, pure mode II and any mixed mode loading conditions in between. Fracture experiments were also conducted on Plexiglas using the DLSP specimen. It is shown that the results obtained from the fracture Tests are consistent very well with mixed mode fracture theories.
Mats Y Svensson - One of the best experts on this subject based on the ideXlab platform.
-
average male and female virtual dummy model biorid and evarid simulations with two seat concepts in the euro ncap low severity rear impact Test Configuration
Accident Analysis & Prevention, 2017Co-Authors: Astrid Linder, Kristian Holmqvist, Mats Y SvenssonAbstract:Soft tissue neck injuries, also referred to as whiplash injuries, which can lead to long term suffering accounts for more than 60% of the cost of all injuries leading to permanent medical impairmen ...
-
simulations with average male and female dummy models with two seat concepts in the euro ncap low severity rear impact Test Configuration
17th International Conference Road Safety On Five Continents (RS5C 2016) Rio de Janeiro Brazil 17-19 May 2016, 2016Co-Authors: Astrid Linder, Kristian Holmqvist, Mats Y SvenssonAbstract:Soft tissue neck injuries, also referred to as whiplash injuries, which can lead to long term suffering are most common in rear impacts. These injuries account for more than 60% of the cost of all injuries leading to permanent medical impairment for the insurance companies with respect to injuries sustained in vehicle crashes. Injury statistics have since the mid-1960s consistently shown that females are subject to a higher risk of sustaining this type of injury than males, on average twice the risk of injury. Furthermore, recently developed anti-whiplash systems have shown to protect females less than males. The diversity of males and females should be addresses when designing and evaluating vehicle safety systems to ensure maximum safety for everyone. This is currently not the case. The norm for crash Test dummies representing humans in crash Test laboratories is an average male. The female part of the population is not represented in Tests performed by consumer information organisations such as NCAP due to the absence of a physical dummy representing an average female. Recently, the world first virtual model of an average female crash Test dummy was developed. In this study, simulations were run with both an average male, and the recently developed average female dummy model, seated in a laboratory vehicle seat. The results of the simulations were compared to earlier published results from the same Test set-up with a vehicle concepts seat. The three crash pulse severities of the Euro NCAP low severity rear impact Test were applied. The motion of the neck, head and upper torso were analysed in addition to the accelerations and the Neck Injury Criterion (NIC). Furthermore, the response of the virtual models was compared to that volunteers and for the average male model, to that of the response of a physical dummy model. Simulations with the male and the female dummy models revealed differences related to the crash severity, as well as between the two dummies in different crash severities in two different seats. For the comparison of the response of the virtual models to the response of the volunteers and the physical dummy model, the peak angular motion of first thoracic vertebra as found in the volunteer Tests and mimicked by the physical dummy were not of the same magnitude in the virtual models.
Sylwester Samborski - One of the best experts on this subject based on the ideXlab platform.
-
Analysis of the end-notched flexure Test Configuration applicability for mechanically coupled fiber reinforced composite laminates
Composite Structures, 2017Co-Authors: Sylwester SamborskiAbstract:Abstract The paper deals with Finite Element Method derivations concerning the mode II critical strain energy release rate ( G IIc ) distribution along delamination front in mechanically coupled laminated composites subjected to the standardized end notched flexure Test, described in the ASTM D7905 Standard. Different stacking sequences were studied in order to obtain six possible forms of coupling matrix B . This revealed possible problems in calculation and interpretation of the G IIc experimental results, while directly using the standardized data reduction scheme. For each sequence several fiber orientation angles were considered, such that a wide fan of possible tendencies in the behavior of coupled composites could be analyzed. The strongest deviation of the G II distributions was observed for the laminated beam models exhibiting simultaneous bending-extension/extension-twisting/shearing-bending coupling, i.e. when the coupling matrix took its B LT form. All simulations were performed in the Abaqus finite element software environment using the virtual crack closure technique. Indications for the experimental Tests were formulated in the conclusions section.
-
numerical analysis of the dcb Test Configuration applicability to mechanically coupled fiber reinforced laminated composite beams
Composite Structures, 2016Co-Authors: Sylwester SamborskiAbstract:This article presents a numerical FE study on the mode I strain energy release rate (SERR, GI) distribution along delamination front in mechanically coupled laminated composites deformed in accordance with the DCB Test Configuration as described in the ASTM D 5528 Standard. The standardized boundary conditions were compared to the freed ones and two kinds of the laminate stacking sequence were considered. The bending–twisting coupling having the superior meaning in the case of mode I experimental Tests was simulated in the Abaqus/CAE finite element software environment with its VCCT facility. The beam models were examined towards the crack front shape and the mode I SERR distribution. The results were compared to those obtained for other coupled, as well as uncoupled layups. Two dimensionless parameters describing GI distribution were introduced and related to the other results. The advantages of the standardized DCB Test setup and possible problems with the results validity in case of the coupled laminates were examined. A usefulness of the results in the allied buckling Tests of composite profiles made of coupled laminates from the point of view of delamination resistance was discussed.
D R Clarke - One of the best experts on this subject based on the ideXlab platform.
-
the thickness and stretch dependence of the electrical breakdown strength of an acrylic dielectric elastomer
Applied Physics Letters, 2012Co-Authors: Jiangshui Huang, Zhigang Suo, Samuel Shian, Roger Diebold, D R ClarkeAbstract:The performance of dielectric elastomer actuators is limited by electrical breakdown. Attempts to measure this are confounded by the voltage-induced thinning of the elastomer. A Test Configuration is introduced that avoids this problem: A thin sheet of elastomer is stretched, crossed-wire electrodes are attached, and then embedded in a stiff polymer. The applied electric field at breakdown, EB, is found to depend on both the deformed thickness, h, and the stretch applied, λ. For the acrylic elastomer investigated, the breakdown field scales as EB = 51 h − 0.25 λ 0.63. The Test Configuration allows multiple individual Tests to be made on the same sheet of elastomer.
-
the thickness and stretch dependence of the electrical breakdown strength of an acrylic dielectric elastomer
Applied Physics Letters, 2012Co-Authors: Jiangshui Huang, Samuel Shian, Roger Mitchell Diebold, D R ClarkeAbstract:The performance of dielectric elastomer actuators is limited by electrical breakdown. Attempts to measure this are confounded by the voltage-induced thinning of the elastomer. A Test Configuration is introduced that avoids this problem: A thin sheet of elastomer is stretched, crossed-wire electrodes are attached, and then embedded in a stiff polymer. The applied electric field at breakdown, EB, is found to depend on both the deformed thickness, h, and the stretch applied, λ. For the acrylic elastomer investigated, the breakdown field scales as EB = 51 h − 0.25 λ 0.63. The Test Configuration allows multiple individual Tests to be made on the same sheet of elastomer.
