<rss version="2.0" xmlns:atom="https://www.w3.org/2005/Atom">
  <channel>
    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
    <description></description>
    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
    </image>
    <item>
      <title>A Hierarchical Exploration of Rib Strain in Dynamic Frontal Thoracic Impacts</title>
      <link>https://trid.trb.org/View/2321651</link>
      <description><![CDATA[Due to high-rate loads placed on the torso during motor vehicle crashes, the human thorax is commonly injured, and resulting rib fractures are linked to fatalities. The goal of this study was to explore the variation in strain modes, magnitudes, and rates of rib levels 3-8 in a dynamic, distributed loading scenario in a series of hierarchical tissue states of 50th percentile males. Strain modes varied by rib level where superior level ribs demonstrated tension on the cutaneous surface, and inferior ribs, rib 8 specifically, experienced compression. Peak strain and peak strain rates varied between rib levels at the anterior and posterior locations (p<0.0001). Intact thoraces generally demonstrated higher peak strain values across rib levels and eviscerated thoraces exhibited higher peak strain rates across rib levels. Rib levels 4-6 experienced higher peak strain than other levels at the anterior location while level 8 experienced higher peak strains at the posterior location.  After whole thorax testing, ribs 4-7 were removed and tested to failure in anterior-posterior bending. Peak strains from individual rib testing did not vary between rib levels 4-7 at anterior or posterior locations (p=0.17 and p=0.79, respectively). This study revealed local deformation patterns across ribs while maintaining the structural integrity of the thorax in distributed loading as well as component testing to failure across rib levels. The results from this study can be used to further understand rib connections during loading events and help to define accurate rib-specific properties to improve the biofidelity of computational human body models.]]></description>
      <pubDate>Wed, 09 Apr 2025 09:51:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2321651</guid>
    </item>
    <item>
      <title>Preliminary Methods for Modeling Stress-Strain Curves of Human Ribs from Structural Dynamic
Bending Tests</title>
      <link>https://trid.trb.org/View/2321649</link>
      <description><![CDATA[It is important to understand and quantify rib behavior in dynamic impacts because thorax injuries are common in motor vehicle crashes and have a high incidence of morbidity and mortality. The goal of this research was to develop a preliminary method to calculate stress and stress-strain curves for which a quantitative model could be used to identify material properties from structural rib tests. Dynamic bending experiments were successfully conducted on 30 whole, mid-level, excised ribs affixed with uniaxial strain gages. A custom MATLAB code was created to calculate stress based on precise cross-sectional geometry at the fracture location. In combination with the strain data, stress-strain curves were created, and a continuous piecewise model was successfully developed to characterize each curve. This model was based on multiple parameters that were used to describe the linear elastic and plastic portion of the stress-strain curve. The model revealed an excellent fit for the stress-strain curves with R² values ranging from 0.985 - 0.999. Because of the high degree of fit, material properties were extracted directly from the model. Elastic modulus values were overestimated by the model and future work is needed to obtain more accurate results. This model seeks to provide a new method of extracting specific material parameters that could be applied to a large, existing experimental rib fracture data set.]]></description>
      <pubDate>Wed, 09 Apr 2025 09:51:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2321649</guid>
    </item>
    <item>
      <title>Viscoelastic Structural Properties of Human Ribs in a Simulated Frontal Impact</title>
      <link>https://trid.trb.org/View/2321650</link>
      <description><![CDATA[The objective of this study was to develop models for exploring viscoelastic structural properties of human ribs in a simulated frontal impact scenario. Three hundred eighty-one ribs from 207 individuals were dynamically tested to simulate anterior-posterior bending in a frontal impact scenario.  Two models, a second order mass-damper-spring model and a piecewise model with mass-damper-spring were proposed to replicate rib reaction force using acceleration, velocity, and displacement data collected during testing.  The piecewise model was composed of two piecewise components: one for the initial loading phase and the other for the subsequent loading phase.  An optimization technique was used to determine parameters of the proposed models by maximizing the coefficient of determination between the proposed models and actual rib responses. Results show the piecewise model successfully mimicked the rib force data (332 of 381 ribs had R-sq ≥ 0.99), while the mass-damper-spring model exhibited less accurate responses (129 of 381 ribs had R-sq ≥ 0.99).  Based on a lack of viscoelastic structural properties of human ribs in the literature, these data should help researchers better understand rib structural behavior in a frontal impact scenario.]]></description>
      <pubDate>Wed, 09 Apr 2025 09:51:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2321650</guid>
    </item>
    <item>
      <title>Characteristics of Vulnerable Occupants Predicted by Rib Structural Properties</title>
      <link>https://trid.trb.org/View/2321648</link>
      <description><![CDATA[Recent advances in safety systems have reduced injuries sustained in motor vehicle crashes. However, unlike other body regions, rib fractures remain a common and serious injury in these events. The goal of this study was to assess the ability of basic individual demographic information to predict thoracic vulnerability. A normative sample of 317 experimentally-tested mid-level human ribs formed the foundation of this study, and the resulting structural properties of percent displacement, peak force, and total energy allowed for rib vulnerability levels to be defined for each property. Thresholds for these levels may be useful for alterations and assessment of rib FE models and improvement of thoracic scaling techniques. Additional results suggest that age, sex, stature, and weight may be utilized with caution for predicting those ribs that are least and most vulnerable, but are not useful for distinguishing those in between. Individuals more likely to have vulnerable ribs include those that are older with smaller body size, particularly females, but this is not always the case. Further investigation is necessary in order to identify more appropriate predictors for occupant vulnerability.]]></description>
      <pubDate>Mon, 07 Apr 2025 17:02:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/2321648</guid>
    </item>
    <item>
      <title>Estimation of Fatigue Parameters and Life Prediction for Orthotropic Steel Deck Based on Reverse Markov Theory</title>
      <link>https://trid.trb.org/View/2516260</link>
      <description><![CDATA[Orthotropic steel deck (OSD) is a widely used lightweight steel structure known for its high load-bearing capacity. However, it is susceptible to cracking, particularly in locations that exhibit structural degradation. In this paper, the reverse Markov method is adopted to identify material parameters and predict the fatigue life of rib-to-rib welds with longitudinal rib-embedded segments in OSD. The structural damage is categorized into five states based on the crack depth, and its state probability distribution and state transfer probability matrix are determined by combining the crack characteristics and service life. This enables the prediction of the crack propagation process during the service life. Then the material parameters C and m can be calculated by substituting the annual crack growth into Paris’ law and combining it with the S-N curve. To illustrate the application of the method, a case study was conducted on the steel box girder of the Xihoumen Bridge. The results indicate that parameter C follows a lognormal distribution with a mean value of 1.90×10−9  MPa−3·m−1/2, while parameter m is determined as 3. Compared with the S-N curve obtained from the test, the calculated S-N curve indicates a fatigue life of approximately 43 years for the welding detail, which aligns much better with the actual performance.]]></description>
      <pubDate>Wed, 26 Mar 2025 09:06:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2516260</guid>
    </item>
    <item>
      <title>Analysing the damping performance of automobile crash dummy ribs</title>
      <link>https://trid.trb.org/View/2464804</link>
      <description><![CDATA[Chest injuries are commonly encountered in traffic accidents, with ribs playing a crucial role in chest impact response. This study focuses on the damping performance of ribs and its influence on chest response during collisions. Employing mechanical bionics principles, the mechanical equivalence of ribs under collision impact was determined. Consequently, a rib impact dynamic model based on equivalent damping theory was developed. This model was integrated with a rib drop hammer impact test system, yielding a numerical solution for the equivalent damping ratio of the rib, quantified as 0.085. Additionally, to validate the accuracy of the rib impact dynamics model, a verification method based on the half-power bandwidth method was proposed. Through the implementation of the rib force hammer impact test, the equivalent damping ratio was determined to be 0.093, showing an 8.6% deviation from the result of the impact dynamics model. These findings not only confirm the validity of the rib equivalent damping theory within the impact dynamics model but also provide theoretical support for the design and improvement of dummy ribs and, potentially, the overall development of crash test dummies.]]></description>
      <pubDate>Mon, 30 Dec 2024 09:58:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/2464804</guid>
    </item>
    <item>
      <title>Analysis of Rib Strain Generation in Frontal Impact at Medium Impact Velocity</title>
      <link>https://trid.trb.org/View/2463804</link>
      <description><![CDATA[The purpose of this study was to clarify the occurrence and mechanism of thoracic injuries in frontal collisions at moderate impact velocities. In the accident case study, AIS 2-3 sternum and rib fractures were identified in frontal collisions at 30 to 40 km/h. The results of FE simulations showed there were differences in the predilection site of plastic strain in the ribs due to differences in body size even for the same crash pulse. The plastic strain distribution was almost the same for the same body size even at lower impact velocities, and the plastic strain values were also similar. The left third rib was subjected to not only bending around the superior-inferior axis of the rib but also torsion around the longitudinal axis, which caused plastic strain in the rib even at relatively low impact velocity.]]></description>
      <pubDate>Wed, 11 Dec 2024 09:05:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2463804</guid>
    </item>
    <item>
      <title>Effect of crack-inclusion interaction on fatigue behavior of rib-to-deck joints in orthotropic steel deck</title>
      <link>https://trid.trb.org/View/2417677</link>
      <description><![CDATA[There are various types of initial defects in weld joints of orthotropic steel deck, which significantly impact the fatigue crack growth behavior of the welds. The traditional single-crack growth model is not appropriate to be utilized for the fatigue investigation of welds containing multiple defects. This study analyzed the dynamic evolution behavior of crack-inclusion interactions in the weld toe of rib-to-deck joints based on the fracture mechanics theory. The influence of defect-related parameters on crack fatigue life was discussed. Numerical simulations and fatigue test were conducted to investigate the dynamic interaction behavior of the crack-inclusion under fatigue loading. A merging criterion for multiple inclusions was proposed to simply the fatigue life analysis of coupled cracks. The numerical results show that the stiff inclusion has a shielding effect on the crack growth. The effect is affected by the relative depth of the crack and inclusion (𝑎₀/𝑅), the interaction spacing of defects (𝑆), and the burial depth of the inclusion (ℎ). The shielding effect becomes negligible under the condition 𝑎₀/𝑅≥3. The fatigue life of the interactive crack increases by up to 23 % compared to single crack. Fully buried inclusions have a limited impact on crack growth. The fatigue life of the interactive crack shows a non-monotonic increase with the quantities of inclusions, with double inclusion clusters. It is demonstrated that the highest shielding effect will increase the fatigue life by 26 %. The proposed merging criterion simplifies the prediction of the fatigue life for welded joint containing multiple inclusions. The numerical result provides a referencing database for fatigue life evaluation of steel structures with multiple welding defects.]]></description>
      <pubDate>Thu, 22 Aug 2024 15:09:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/2417677</guid>
    </item>
    <item>
      <title>Shear Behavior of Y-Shaped Perfobond Rib Shear Connector with UHPC Grout</title>
      <link>https://trid.trb.org/View/2394507</link>
      <description><![CDATA[To improve shear capacity, as well as reduce on-site casting and steel consumption, a novel Y-shaped perfobond rib (Y-PBL) shear connector with ultra-high-performance concrete (UHPC) grout was proposed. The shear behavior of the Y-PBL shear connector was investigated by six groups of pushout specimens. Their failure modes, load–slip curves, load–separation curves, strain analysis, and shear transfer mechanisms were discussed. Subsequently, finite-element analysis (FEA) models were established to study the effect of parameters on the shear behavior of the Y-PBL shear connector, as well as to compare the shear capacity contributions with straight-shaped PBL (S-PBL) shear connectors. Analytical models were proposed to predict the shear capacity of the Y-PBL shear connector. The results reveal that the proposed Y-PBL shear connector has superior shear capacity and stiffness. The contribution of the perforating rebar is minor compared with the end-bearing effect of UHPC. The analytical predictions agree well with the experimental and FEA results. This study can be used to guide the design and application of the Y-PBL shear connector in steel-concrete composite bridges.]]></description>
      <pubDate>Thu, 01 Aug 2024 11:28:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/2394507</guid>
    </item>
    <item>
      <title>Biomechanical Response Targets of Adult Human Ribs in Frontal Impacts</title>
      <link>https://trid.trb.org/View/2321652</link>
      <description><![CDATA[This article reports on a study undertaken to generate biomechanical response targets for human rib response, taking into consideration age, sex, and body size.   The authors note that, while thoracic biomechanics have been studied in detail, there are no robust biomechanical response targets for ribs that include these factors.  In this study, 261 ribs from 171 individuals were dynamically loaded to failure in anterior–posterior bending.  The authors found that force and displacement at the time of fracture in young adults were greater than in older adults. Sex differences were found, but only in those subjects over 40 years old. The authors conclude that the biomechanical targets established by this study can be used to develop computational thorax and rib models.]]></description>
      <pubDate>Wed, 20 Mar 2024 17:10:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/2321652</guid>
    </item>
    <item>
      <title>Prediction of All Rib Deflections of THOR-ATD by Means of Deep Neural Network Model</title>
      <link>https://trid.trb.org/View/2211671</link>
      <description><![CDATA[The fatality rate of thoracic injury for elderly occupants in vehicle accidents is significantly high. Its major cause is the rise of internal organ injury rates due to an increase in the number of fractured ribs (NFR). Therefore, NFR reduction is crucial to enhance elderly occupant protection and is one of the key issues for achieving zero fatalities. In order to improve NFR prediction accuracy, the previous study proposed the criterion using the weighted averaged displacement of all ribs (WADAR), which indicated a higher correlation coefficient with NFR than that of the criterion, Rmax, using four Infra-Red Telescoping Rod for the Assessment of Chest Compression (IR-TRACC) installed on the thorax of the Test device for Human Occupant Restraint Anthropometric Test Dummy (THORATD). While WADAR requires all rib deflections, it is difficult to install IR-TRACCs on all ribs inside the limited space in the thorax of THOR-ATD. The objective of this research is to predict the deflections of all ribs by means of a neural network model using time-histories of rib deflections from four IR-TRACCs and the crash velocity without any installation of additional measurement devices. The architecture of the neural network model is based on U-Net, which is one of the convolutional neural network models. The model was trained by time-historical X, Y and Z displacements of 14 ribs and the crash velocity derived from the 56 FEM simulation data, which represented frontal and oblique sled experiments with THORATD. The model learned the physical relationships among the ribs with and without IR-TRACCs. The predicted rib deflections were validated by the THOR-ATD experiment, where the displacements of the 2nd to 6th ribs on the left side were measured three-dimensionally by the set of two cameras installed on the upper and lower thoracic spines. The predicted deflections during 0 to 150 ms were processed into a resultant deflection and compared to the actual deflection through the 2nd to 6th ribs on the left side. The maximum differences in the peak deflection were 2.3 mm, respectively. Furthermore, the root mean square error (RMSE) was calculated at each rib for prediction accuracy evaluation, which resulted in minimum and maximum RMSE of 0.6 mm and 2.7 mm, respectively. Although the number of training datasets was small, the neural network model trained by FEM simulation data could predict all the rib deflections with small error without physical measurement devices.]]></description>
      <pubDate>Tue, 08 Aug 2023 13:16:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2211671</guid>
    </item>
    <item>
      <title>Probability Functional Evaluation of Chest Injury Based on Rib Strain of Human Body Model in Frontal Collision</title>
      <link>https://trid.trb.org/View/2211670</link>
      <description><![CDATA[This study examined the influence of chest restraint force on the chest injury probability of the human body model (HBM) in frontal collision. Total Human Model for Safety (THUMS) Version 4.1 AM50 was seated in the driver's seat of a finite element (FE) model represented a prototype midsize vehicle, and frontal collision simulations were performed. The probability of three or more rib fractures from 20YO to 80YO were predicted from simulated THUMS rib strain based on prior work. The probability increased with age, and showed a tendency to rise sharply beginning around the 60YO in particular. The trend was shown to be similar to the probability predicted statistically from the NASS-CDS field accident data. Furthermore, a collision simulation was also conducted in which the restraint balance between the seatbelt and airbag was changed while keeping the same amount of forward excursion of the occupant. As a result, it was found that the probability of rib fracture was reduced by the combination of reducing the seatbelt force and increasing the initial restraint force of the airbag compared to a base specification. This was due to the improved ride-down efficiency and reduced seatbelt contact force, which reduced the strain on the upper ribs on the path of seatbelt.]]></description>
      <pubDate>Tue, 08 Aug 2023 13:16:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2211670</guid>
    </item>
    <item>
      <title>Female-specific Response &amp; Injury Risk (Thorax/Ribs &amp; Abdomen)</title>
      <link>https://trid.trb.org/View/2050295</link>
      <description><![CDATA[This project involves testing small female post-mortem human subjects (PMHS) to evaluate thorax response prediction using new rib-based scaling method; assessing existing abdomen data/collecting more PMHS data to statistically compare female vs male pressure-based injury risk functions; and data analysis/development of rib fracture vulnerability metric using age and sex]]></description>
      <pubDate>Tue, 25 Oct 2022 10:24:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2050295</guid>
    </item>
    <item>
      <title>The influence of impact speed on chest injury outcome in whole body frontal sled impacts</title>
      <link>https://trid.trb.org/View/1769380</link>
      <description><![CDATA[While the seatbelt restraint has significantly improved occupant safety, the protection efficiency still needs further enhance to reduce the consequence of the crash. Influence of seatbelt restraint loading on chest injury under 40 km/h has been tested and documented. However, a comprehensive profiling of the efficiency of restraint systems with various impact speeds has not yet been sufficiently reported. The purpose of this study is to analyse the effect of the seatbelt loadings on chest injuries at different impact speeds utilizing a high bio-fidelity human body Finite Element (FE) model. Based on the whole-body frontal sled test configuration, the current simulation is setup using a substitute of Post-Mortem Human Subjects (PMHS). Chest injury outcomes from simulations are analysed in terms of design variables, such as seatbelt position parameters and collision speed in a full factorial experimental design. These outcomes are specifically referred to strain-based injury probabilities and four-point chest deflections caused by the change of the parameters. The results indicate that impact speed does influence chest injury outcome. The ribcage injury risk for more than 3 fractured ribs will increase from around 40 to nearly 100% when the impact speed change from 20 to 40 km/h if the seatbelt positioned at the middle-sternum of this study. Great injuries to the chest are mainly caused by the change of inertia, which indicates that chest injuries are greatly affected by the impact speed. Furthermore, the rib fracture risk and chest deflection are nonlinearly correlated with the change of the seatbelt position parameters. The study approach can serve as a reference for seatbelt virtual design. Meanwhile, it also provides basis for the research of chest injury mechanism.]]></description>
      <pubDate>Tue, 25 May 2021 16:20:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/1769380</guid>
    </item>
    <item>
      <title>Evaluation of Rib Deformation of THOR Dummy in Seat Belt Loadings</title>
      <link>https://trid.trb.org/View/1840335</link>
      <description><![CDATA[The chest of occupants is frequently injured in car crashes. In this research, the chest deflection in a seat belt loading was compared in THUMS, Hybrid III and THOR. There are three modes of rib deformation in THUMS resulted from different load of the seat belt. The first mode of rib deformation is caused by a load applied to the costal cartilage, the mode pattern is caused by load applied to the front edge of rib and the third was S-shaped deformation caused by load applied to the side of rib. Though the S-shaped rib deformation was observed in THOR, the chest deflection of the THOR did not represent rib fracture risks because the measurement points are located at the anterior edge of the rib.]]></description>
      <pubDate>Wed, 21 Apr 2021 16:19:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/1840335</guid>
    </item>
  </channel>
</rss>