Joint Stress Research Articles

The anterior talofibular ligament ratio was greater in young men with generalized joint laxity than in those without generalized joint laxity.

This study aimed to evaluate the relationship between generalized joint laxity (GJL) and stress ultrasonographic (US) findings of the anterior talofibular ligament (ATFL) of healthy young men. The ATFL lengths of healthy young men were consecutively measured in the stress and nonstress positions. The ATFL ratio was calculated as an indicator of lateral ankle laxity. GJL was evaluated using the Beighton score (BS), and a BS of ≥ 5 was considered GJL. The manual anterior drawer test (ADT) was also performed. The results of stress US and ADT were compared between subjects with and without GJL, and the correlation between GJL and US findings was examined. A total of 13 subjects with GJL and 95 without GJL were included in the study. The mean BSs in the GJL and no-GJL groups were 5.9 ± 0.9 and 1.1 ± 1.3, respectively (p < 0.0001). The GJL group showed a higher grade of ADT than the no-GJL group (p < 0.0001). Significant differences were found in the stress ATFL length (23.6 ± 1.8mm vs. 21.7 ± 1.8mm, p = 0.002) and ATFL ratio (1.15 ± 0.06 vs. 1.07 ± 0.03, p < 0.0001) between the GJL and no-GJL groups. Spearman's correlation coefficients showed a moderate correlation between the BS and ATFL ratio (r = 0.45, p < 0.0001). The present study showed significant differences in the ATFL ratio and stress ATFL length between young men with and without GJL. The BS was moderately correlated with the lateral ankle laxity in this population. Level IV.

Effects of cavitation jet peening treatment on the residual stress and fatigue properties of SAF2205 cruciform welded joints

AbstractThe cruciform welded joint is a weak position of filter press to cause fatigue failure under cyclic conditions. In this study, cavitation jet peening (CJP) treatment is proposed to improve the fatigue life of SAF2205 cruciform welded joints. The effects of different CJP treatment positions on the residual stress, microstructure, and microhardness were studied. The results show that different CJP treatment positions have different on residual stresses and fatigue life. The order of the residual stress in fracture position from large to small is the fully treated specimen, untreated specimen, one‐sided treated specimen, and diagonal treated specimen, which is exactly opposite to the order of fatigue life from large to small. After the diagonal CJP treatment, the fatigue life is increased by up to 242.19%, and the residual stress at the weld toe is reduced by more than 80%. A strengthening layer with thicknesses of about 400 μm is formed.

Real‐time measurement of welding residual stress relaxation based on strain‐controlled fatigue test

AbstractFatigue‐induced variation of residual stress (RS) in welded joints is inevitable and has significant influence on fatigue behavior. The widely used technologies (e.g., X‐ray diffraction) can only test surface RS of specimen at unloading or certain holding load condition. In this study, an approach of measuring equivalent RS in real time during fatigue cycling is proposed based on strain‐controlled fatigue with strain ratio of −1. Under applied waveform starting with tensile strain, tensile RS in a welded joint continuously relaxes with fatigue cycles, but compressive RS first increases then relaxes. Both tensile and compressive RSs rapidly change in the first few cycles and then gradually relax to a steady state in which accumulated plastic strain is linearly correlated to amount of RS relaxation during fatigue cycling.

Comparison of the Biomechanical Effect of the FFX Device Compared With Other Lumbar Fusion Devices: A Finite Element Study.

Lumbar decompression can result in postsurgical instability and spondylolisthesis in patients with lumbar spinal stenosis (LSS). While pedicle screw (PS) constructs improve stability and support fusion, their use can lead to adjacent level degeneration due to rigidity and resultant overload of anatomical structures. The FFX device is a facet spacer designed to be a less invasive alternative for obtaining fusion compared with PS. The present study aimed to compare biomechanical performance of the FFX device to different lumbar spine procedures using the finite element (FE) method. Comparative biomechanical study by FE method. An FE model for the lumbar spine was developed and validated to assess vertebral displacement and stress variations in the facet joints and discs following surgery. Modeled scenarios included a healthy spine as a reference model, laminectomy (LAM), and prior to/following L4-L5 fusion for LAM + FFX and LAM + PS. LAM increased displacement compared with the healthy spine and both instrumented spine procedures. Facet joint stress at adjacent levels for LAM + PS was significantly higher than with LAM + FFX prior to fusion (+13.5% for L3-L4; +15.7% for L5-S1). Adjacent level disc stress at L5-S1 was 7.7% higher for LAM + PS vs LAM + FFX. Adjacent level facet joint and disc stresses for LAM + FFX were equivalent to LAM + PS once fusion occurred. Instrumented spine fixation prevents the risk of lumbar instability associated with LAM alone. Compared with PS, the FFX device is a less invasive alternative for the treatment of LSS, which potentially lowers the risk of adjacent segment degeneration prior to fusion that provides equivalent stability once fusion is achieved.

Hot deformation behavior and strain compensation constitutive model of equiaxed fine grain diffusion-welded micro-duplex TC4 titanium alloy

In this work, two-stage diffusion bonding of micro-duplex TC4 titanium alloy was carried out to study the flow behavior and constitutive models of the bonding joint and the base metal after the same thermal cycling during the hot forming process. Microstructure and mechanical properties test were used to verify the good quality of the equiaxed fine grain diffusion-welded TC4 alloy. Quasi-static tensile experiment was carried out at temperatures ranging from 750–900 °C and strain rates of 0.0001–0.1 s−1. The joint showed the weak dynamic recovery at strain rates of 0.01–0.1 s−1 and temperatures of 750–850 °C. At strain rates of 0.0001–0.001 s−1 and temperatures of 850–900 °C, the flow stress of joint presented steady-state characteristics. Different deformation conditions lead to the remarkable difference of dynamic softening performance between the joint and heat-treated base metal, but the flow stress in elastic and strain hardening stages exhibited similar behavior. The strain compensated Arrhenius-type constitutive models of TC4 joint and heat-treated base metal were developed respectively. The fifth-order polynomial functions between the material property correlation coefficients and strain were obtained. The models have shown good correlation, with correlation coefficient values of 0.984 and 0.99. The percentage average absolute relative error for the models were found to be 10% and 9.46%, respectively.

The effects of increased forward trunk lean during stair ascent on hip adduction and internal rotation in asymptomatic females

BackgroundIncreased hip adduction and internal rotation can lead to excessive patellofemoral joint stress and contribute to patellofemoral pain development. The gluteus maximus acts as a hip extensor, abductor, and external rotator. Improving hip extensor use by increasing one’s forward trunk lean in the sagittal plane may improve frontal and transverse plane hip kinematics during stair ascent. Research questionDoes increasing forward trunk lean during stair ascent affect peak hip adduction and internal rotation? MethodsTwenty asymptomatic females performed five stair ascent trials (96 steps/min) on an instrumented stair using their self-selected and forward trunk lean postures. Three-dimensional kinematics (200 Hz) and kinetics (2000 Hz) were recorded during the stance phase of stair ascent. Biomechanical dependent variables were calculated during the stance phase of stair ascent and included peak forward trunk lean, hip flexion, hip adduction, hip internal rotation angles, and the average hip extensor moment. ResultsDuring the forward trunk lean condition, decreases were observed for peak hip adduction (MD = 2.8˚; 95% CI = 1.9, 3.8; p < 0.001) and peak hip internal rotation (MD = 1.1˚; 95% CI = 0.1, 2.2; p = 0.04). In contrast, increases were observed during the forward trunk lean condition for the peak forward trunk lean angle (MD = −34.7˚; 95% CI = −39.1, −30.3; p < 0.001), average hip extensor moment (MD = −0.5 N·m/kg; 95% CI = −0.5, −0.4; p < 0.001), and stance time duration (MD = −0.02 s; 95% CI = −0.04, 0.00; p = 0.017). SignificanceIncreasing forward trunk lean and hip extensor use during stair ascent decreased peak hip adduction and internal rotation in asymptomatic females. Future studies should examine the effects of increasing forward trunk lean on hip kinematics, self-reported pain, and function in individuals with patellofemoral pain.

Patellofemoral Joint Loading in Forward Lunge With Step Length and Height Variations.

The objective was to assess how patellofemoral loads (joint force and stress) change while lunging with step length and step height variations. Sixteen participants performed a forward lunge using short and long steps at ground level and up to a 10-cm platform. Electromyography, ground reaction force, and 3D motion were captured, and patellofemoral loads were calculated as a function of knee angle. Repeated-measures 2-way analysis of variance (P < .05) was employed. Patellofemoral loads in the lead knee were greater with long step at the beginning of landing (10°-30° knee angle) and the end of pushoff (10°-40°) and greater with short step during the deep knee flexion portion of the lunge (50°-100°). Patellofemoral loads were greater at ground level than 10-cm platform during lunge descent (50°-100°) and lunge ascent (40°-70°). Patellofemoral loads generally increased as knee flexion increased and decreased as knee flexion decreased. To gradually increase patellofemoral loads, perform forward lunge in the following sequence: (1) minimal knee flexion (0°-30°), (2) moderate knee flexion (0°-60°), (3) long step and deep knee flexion (0°-100°) up to a 10-cm platform, and (4) long step and deep knee flexion (0°-100°) at ground level.

An investigation on residual stress and fatigue life assessment of T-shape welded joints

This paper aims to quantitatively evaluate the residual stress and fatigue life of T-type welded joints with a multi-pass weld in different direction. The main research objectives of the experimental test were to test the residual stress by changing direction along with multiple wielding passes and determine the fatigue life of the welded joints. The result shows that compressive residual stress increases in the sample gradually from single-pass weld to double and triple-pass weld. Moreover, the fatigue life of the specimen also gradually improves with an increasing number of welding passes. Performing multi-pass welding in different directions affects the material’s residual stress and fatigue life, which is an essential factor to consider for assuring the strength of the welded joint.

Artificial Neural network-based prediction of SCF at the Intersection of CFST Y-joints

Stress concentration factors (SCFs) are used to quantify the hot-spots stress in tubular joints with circular hollow section for fatigue assessment, which are always obtained by finite element analysis or specimens testing. According to design specifications, complex formulas are recommended to calculate the SCFs at special locations of the intersection lines weld toe of tubular joints for individual load cases. To improve the fatigue performance of the joint, the concrete is filled in the chord to form a concrete-filled steel tube (CFST) joint. The capability of back-propagation neural network-based (BPNN) model in calculation of the SCFs in CFST Y-joints was investigated in this study. Three hundred FE numerical models were investigated to evaluate the effects of changes in different geometrical parameters on the SCFs of CFST Y-joint and the FEA results were used to train and test the neural networks. The nonlinear mapping relationships between the affecting variables and the SCFs distributions were established. Research results showed that SCFs prediction results of CFST Y-joints from BPNN models are close to the FE results, and properly trained and well calibrated BPNN can be reliable alternatives to complicated SCFs equations for predicting SCFs distribution at intersection line of CFST Y-joints.

Contribution of joint tissue properties to load-induced osteoarthritis

ObjectiveClinical evidence suggests that abnormal mechanical forces play a major role in the initiation and progression of osteoarthritis (OA). However, few studies have examined the mechanical environment that leads to disease. Thus, using a mouse tibial loading model, we quantified the cartilage contact stresses and examined the effects of altering tissue material properties on joint stresses during loading. DesignUsing a discrete element model (DEA) in conjunction with joint kinematics data from a murine knee joint compression model, the magnitude and distribution of contact stresses in the tibial cartilage during joint loading were quantified at levels ranging from 0 to 9 N in 1 N increments. In addition, a simplified finite element (FEA) contact model was developed to simulate the knee joint, and parametric analyses were conducted to investigate the effects of altering bone and cartilage material properties on joint stresses during compressive loading. ResultsAs loading increased, the peak contact pressures were sufficient to induce fibrillations on the cartilage surfaces. The computed areas of peak contact pressures correlated with experimentally defined areas of highest cartilage damage. Only alterations in cartilage properties and geometry caused large changes in cartilage contact pressures. However, changes in both bone and cartilage material properties resulted in significant changes in stresses induced in the bone during compressive loading. ConclusionsThe level of mechanical stress induced by compressive tibial loading directly correlated with areas of biological change observed in the mouse knee joint. These results, taken together with the parametric analyses, are the first to demonstrate both experimentally and computationally that the tibial loading model is a useful preclinical platform with which to predict and study the effects of modulating bone and/or cartilage properties on attenuating OA progression. Given the direct correlation between computational modeling and experimental results, the effects of tissue-modifying treatments may be predicted prior to in vivo experimentation, allowing for novel therapeutics to be developed.

Fatigue performance of rib-to-deck joints in orthotropic steel deck with PWHT

Post-weld heat treatment (PWHT) displays potential for enhancing the fatigue strength of rib-to-deck (RD) welded joints in orthotropic steel decks (OSDs) by mitigating welding residual stress. In this study, residual stress measurements, fatigue tests, and fracture analyses were performed to investigate the influence of PWHT on the welding residual stress and fatigue strength of RD joints. Eighteen full-scale specimens were fabricated, i.e. ten PWHT-processed specimens and eight as-welded specimens without additional treatment. Hole drill (HD) and X-ray diffraction (XRD) were used to measure the residual stress in four PWHT specimens and four as-welded specimens. The PWHT specimen showed a reduction in the peak residual stress by 76% and 78% in the HD and XRD results, respectively. Fatigue tests were carried out on the six PWHT specimens and four as-welded specimens. The comparison was made between the two specimen types using the mean value of equivalent fatigue strength derived at 2 million cycles. The results indicated that PWHT improved the mean equivalent fatigue strength of RD joints by 23% and 33% under nominal stress and hot-spot stress, respectively. Parametric investigations were carried out using finite element-based fracture analysis to elucidate the influence of residual stress mitigation on fatigue crack growth in RD joints. The result indicated a significant decrease in the crack growth rate owing to residual stress mitigation. Such a decrease enhances the fatigue strength of RD joints.

Synergetic effect of adhesive bonding and welding on fracture load in hybrid joints

Joining of components with adhesive bonding (AB) is a wide-spread technique that distributes the load over a greater area than mechanical joints. However, peak stresses at the overlap edges can lead to premature failure. In the current study a novel procedure was used to solve this problem by using a hybrid weld joint to decrease the stress concentration at the edges. Due to the different mechanisms of joining, AB and welding cannot be combined in one place since interactions degrade the mechanical performance of both joints. Therefore, in this study, the focus was to manufacture a hybrid joint where additional sheets were manually welded at the overlap edges of the adhesively bonded lap joint. By doing so, bilateral effects such as burning of the adhesive by welding and weld defect formation due to presence of adhesive layer were eliminated. Tensile shear tests were carried out to determine the fracture load of the adhesive, welded and hybrid joint. The fracture surfaces were examined to determine the fracture mechanism. Numerical simulations were performed with stress analysis and fracture prediction to observe the stress distribution. The hybrid joint showed superior mechanical tensile strength and deformation, when compared against the AB and welded joint. The simulation results showed that the location of the maximum stress in the hybrid joint is in the middle of the span which is in contrary to AB joints wherein the maximum stress occurs at the edge. This caused a synergetic effect of both AB and welding leading to superior mechanical properties. The resulting findings potentially provide insights for the development of new hybrid joining configurations delivering improved performance.

Blue laser welding of 7075-T6 aluminum alloy and carbon fiber reinforced polyetheretherketone

Laser welding was employed to join aluminum alloys and carbon fiber reinforced polymers (CFRP) inexpensively and quickly in lightweight automobiles, especially in the field of new energy vehicles. In recent years, a new way to obtain stronger high-reflection alloy laser welded joints is blue laser welding (BLW). An innovative comparative experiment was conducted between blue laser welding (BLW) and fiber laser oscillation welding (FLOW), using 7075-T6 aluminum alloy and carbon fiber reinforced polyetheretherketone (CFRP-PEEK) as study materials, and the laser welding mechanism is explained. It was concluded that the maximum tensile force of the BLW joint was 478 N, which is higher than the 290 N tensile force of FLOW. In addition, the maximum residual stress in the BLW joint is 325 MPa, which is lower than that of FLOW. The mechanism affecting the strength of the joint is the presence of a larger number and size of bubble defects inside the FLOW melt pool, and the presence of a demarcation line between the columnar and equiaxed crystals around these bubble defects is observed. This boundary line means that there is a large temperature difference. Combined with the finite element simulation results, the existence of the temperature difference leads to a different solidification sequence around the bubble defect inside the molten pool, so stress concentration occurs. Therefore, the interface of the FLOW joint is not tightly combined, and a gap phenomenon occurs. Furthermore, when the laser power increases, PEEK resin is extruded into the melt pool as the melt pool size approaches that of the aluminum alloy, as observed in the BLW joint. The same demarcation line between columnar and equiaxed crystals structure was observed in the PEEK resin, so that the stress concentration around the PEEK resin can lead to weakened joints in high power welding.

Influence of strain-hardening models and slopes on the predicted residual stresses in structural steel S235 weldments

The objective of this research is to systematically understand how strain-hardening models and phase- and temperature-dependent strain-hardening slopes affect the computed residual stresses in single-pass welded joints made of the widely used structural steel S235. Both experimental methods and numerical simulation have been utilized for investigation. The results reveal that the material plasticity model has a massive effect on the predicted welding residual stresses (WRS). The calculated magnitude of WRS in the base metal (BM) adjacent to the weld zone inside the plate is largest when the isotropic hardening model is used, while it is smallest applying the kinematic hardening model. The comparison of predictions with measurements shows that the isotropic hardening model can predict WRS more accurately for S235 steel. The change in the temperature-dependent strain-hardening slopes of the generated phases (austenite and bainite in this case) have practically no impact on the predicted WRS. The calculated longitudinal residual stress (LRS) amount in BM nearby the weld zone is highly sensitive to the applied strain-hardening slopes of the initial microstructure (ferrite here), while that of transverse residual stress (TRS) is not. In contrast to the strain-hardening slopes of the initial microstructure at elevated temperatures, that at room temperature plays a crucial role in the simulated LRS. In this study, guidance is provided on how the phase- and temperature-dependent strain-hardening slopes of a specific steel can be determined economically and reliably in numerical welding simulation.

Effects of Limb Dominance on Patellofemoral Joint Loading During Gait at 12 Weeks After Anterior Cruciate Ligament Reconstruction.

Background:Patellofemoral joint complications have commonly been reported in long-term outcome studies for anterior cruciate ligament reconstruction (ACLR); however, the biomechanics in the early phases of rehabilitation that could be associated with the development of these abnormalities is unclear. Limb dominance may affect the biomechanics of the knee joint in patients after ACLR.Purpose:To compare knee joint loading between surgical and nonsurgical limbs at 12 weeks postoperatively in patients who underwent ACLR on either their dominant limb (ACL-D) or nondominant limb (ACL-ND).Study Design:Controlled laboratory study.Methods:Included were 54 patients (32 ACL-D and 22 ACL-ND). Peak and integrated patellofemoral joint stress (PFJS), peak patellofemoral joint reaction force (PFJRF), and peak knee extension moment (KEM) were assessed during the stance phase of gait while participants walked on a 10-m runway at a self-selected speed.Results:The surgical limb of the ACL-D group had significantly decreased peak PFJS (P < .001), integrated PFJS (P < .001), peak PFJRF (P < .001), and peak KEM (P < .001) compared to the nonsurgical limb. The surgical limb of the ACL-ND group demonstrated significantly increased peak PFJS (P = .001), integrated PFJS (P = .023), peak PFJRF (P < .001), and peak KEM (P = .001) compared to the nonsurgical limb. For the surgical limb, the ACL-ND group demonstrated significantly greater peak PFJS (P < .001), peak PFJRF (P < .001) , (PFJRF [P<.001]) and peak KEM (P < .001) than the ACL-D group. For the nonsurgical limb, the ACL-D group demonstrated greater peak PFJS (P < .001), integrated PFJS (P = .023), peak PFJRF (P = .003), and peak KEM (P < .001) than the ACL-ND group.Conclusion:Significantly larger knee joint loading on the surgical limb of the ACL-ND group and smaller knee joint loading on the surgical limb of the ACL-D group were observed compared to the contralateral nonsurgical limb, which suggests that limb dominance has a key role in loading at the knee joint during gait.Clinical Relevance:Altered knee joint loading during gait at 12 weeks after ACLR may lead to the development of patellofemoral joint abnormalities.

Effect of the IMC layer geometry on a solder joint thermomechanical behavior

PurposeIn a printed circuit board assembly (PCBA), the coefficient of thermal expansion (CTE) mismatch between the solder joint materials has a detrimental impact on reliability. The mechanical stresses caused by the thermal changes of the assembly lead to fatigue and sometimes the failure of the solder joints. The purpose of this study is to propose a novel pad design to obtain an interrupted solder/substrate interface, to improve the PCBA reliability.Design/methodology/approachAn interruption in the continuous intermetallic compound (IMC) layer of a solder joint was implemented, by the deposition of a silicone film in the pad, changing its geometry. That change allows a redistribution of stresses in the most ductile zone of the solder joint, the solder. The stress concentration at the solder/substrate interface is reduced, as well as the general state of stress at the solder joint.FindingsA new way was developed to reduce the stress on the solder joints, caused by thermal variations, because of the different components CTEs mismatch. This new method consists of interrupting the IMC layers of the solder joint, strategically, redirecting the usual stresses to a more ductile area of the joint, the solder. This is an innovative method that allows increase the lifetime of PCBAs and the equipments.Originality/valueIn this study, a new pad design concept for higher solder joint reliability was developed to reduce the shear stress in the solder joints because of the CTE mismatch between all the solder joint components.

Seismic Response Analysis of Anchor Joint in Shield–Driven Tunnel Considering Soil–Structure Interaction

The seismic behavior of the anchor joint in shield-driven tunnel is very difficult to determine with the conventional methods due to the extensive simplifications. This paper proposed an improved approach to investigate the seismic response of the anchor joint, considering both the soil-structure-interaction effect and the actual geometric features. Two three-dimensional numerical models were established, including the soil-tunnel system and the refined model of the anchor joint. A seismic analysis study was first conducted on the soil-tunnel model under different seismic input waves to obtain the responses of the joint opening and offset. Then, these results were imposed on the refined model of anchor joint to further examine its detailed performance under seismic excitations. The joint opening and offset under earthquake excitations from different directions were discussed. The distribution characteristics of the stress of the anchor joint were interpreted. Finally, safety evaluations on the anchor joint were executed based on the overall seismic responses. The results show that the maximum opening and offset of the anchor joint under the two-directional horizontal earthquake are greater than those under the unidirectional conditions, while different deformation trends are observed for the joints at distinct locations. The maximum opening of the anchor joint can reach 0.73 mm, whereas the peak offset is only 0.35 mm. The local plastic strain of the anchor joint increases under the seismic action, but all of the joints are still kept in the safe state under the most unfavorable conditions. The developed method in this paper can also be accessed by the seismic study on other types of joints with complex structural components in shield tunnels.

Biomechanical comparison of different interspinous process devices in the treatment of lumbar spinal stenosis: a finite element analysis

BackgroundLumbar spinal stenosis (LSS) is a common disease among elderly individuals, and surgery is an effective treatment. The development of minimally invasive surgical techniques, such as the lumbar interspinous process device (IPD), has provided patients with more surgical options.ObjectiveTo investigate the biomechanical properties of different IPDs, including BacFuse, X-Stop and Coflex, in the treatment of LSS.MethodsBased on the computed tomography images of a patient with LSS, four finite element (FE) models of L3-S5 were created in this study. The FE models included a surgical model of the intact lumbar spine and surgical models of the lumbar IPDs BacFuse, X-Stop, and Coflex. After validating the models, they were simulated for four physiological motions: flexion, extension, lateral bending and axial rotation, and range of motion (ROM). Stress distribution of discs and facet joints in each segment, stress distribution of the spinous process in the operated section, and stress distribution of the internal fixation were compared and analysed.ResultsCompared to the model of the intact lumbar spine, the other three models showed a decrease in ROM and disc and facet joint stresses in the surgical segment during movement and an increase in ROM and disc and facet joint stresses in the adjacent segments. These effects were greater for the proximal adjacent segment with BacFuse and more pronounced for the distal adjacent segment with Coflex, while X-Stop had the greatest stress effect on the spinous process in the surgical segment.ConclusionBacFuse, Coflex and X-Stop could all be implemented to effectively reduce extension and disc and facet joint stresses, but they also increase the ROM and disc and facet joint stresses in adjacent segments, which may cause degeneration.

Parametric formulae for stress concentration factor and clamping-induced stress of butt-welded joints under fatigue test condition

Parametric formulae for stress concentration factor and clamping-induced stress of butt-welded joints under fatigue test condition

Next-Generation High-Density PCB Development by Fan-Out RDL Technology

High-density interconnect (HDI) printed circuit boards (PCBs) are in high demand for smartphones, particularly those with fifth generation (5G) functionality, due to their smaller form factors, higher interconnection densities, and improved integrative ability. Various advanced PCB technologies are available, including HDI PCBs and substrate-like PCBs (SLPs). However, even for substrate-like PCBs, the line width (L) and spacing (S) of the copper traces are limited to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$25~\mu \text{m} / 25~\mu \text{m}$ </tex-math></inline-formula> , and fine-line development also faces yield and cost challenges. Accordingly, the present study utilizes an redistribution layer (RDL) first fabrication process to develop a fine line width/spacing ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10~\mu \text{m} / 10~\mu \text{m}$ </tex-math></inline-formula> ) Fan-out interposer (FOI) on PCB architecture with a higher I/O (Input/Output) density, greater yield, and lower cost. A three-dimensional (3D) ANSYS finite element (FE) model combined with volume fractions approach applied to equivalent thermomechanical properties of the multilayer RDL is introduced. The validity of the simulation model is confirmed by comparing the numerical results for the out-of-plane deformation of the top surface of the FOI with the experimental observations. Then, the effects of five design parameters on the warpage and solder joint stress performance of the FOI-PCB architecture are identified through parametric analysis. Finally, a second-order response surface methodology (RSM) model and Box-Wilson central composite design (CCD) method are employed to examine the interactive effects of the structural design factors of the FOI-PCB architecture on the FOI warpage under typical manufacturing thermal loading conditions. It is shown that a smaller overall size of the FOI is beneficial in reducing the warpage by minimizing the coefficient of temperature expansion (CTE) mismatch between the interposer and the PCB.