Jérôme Molimard

• PhD
• Professor (Full) at Mines Saint-Étienne

Background: Although impairments in dorso-lumbar spine mobility have been previously reported in patients with low back pain, its exact mechanism is not yet clear. Therefore, the purpose of this systematic review and meta-analysis is to investigate and compare spinal kinematics between subjects with and without low back pain and identify appropria...

A comparative study of eight different lumbar belts, which are representative of the French market, was carried out on four typical morphologies of patients to assess their therapeutic effects and identify the correlation between the therapeutic parameters and mechanical ones. Four typical morphologies were chosen among 15 patients that had been ch...

Constitutive models have been developed to describe damage behavior of materials, including soft tissues. However, most of them do not include crack opening and progression, which can be overcome using phase field damage method. Unfortunately, due to the complex behavior of soft tissues, damage parameters identification from experiments is very cha...

Background: The present study aimed to classify the relative contributions of four biomechanical factors—the root-end filling material, the apical preparation, the root resection length, and the bone height—on the root stresses of the resected premolar. Methods: A design of experiments approach based on a defined subset of factor combinations was c...

Predicting the damage in soft tissues remains a major challenge because of its computational difficulty and the need to involve inverse methods for parameter identification. One of the main limitations is the transition from damage to fracture which can be overcome using the diffuse phase field method [1]. Due to the unstable propagation of the cra...

Low back pain represents a major economic and societal challenge due to its high prevalence. Lumbar orthoses are one of the recommended treatments. Even if previous results showed their clinical effects, the detailed mode of action is still poorly known, making the device design difficult. A renewed instrumentation and experimental protocol should...

Interface pressure applied by compression bandages is the therapeutic action of the treatment of some venous or lymphatic pathologies. The so-called Static Stiffness Index, which quantifies the pressure increase from supine to standing position, is usually used to differentiate compression bandages. It was hypothesized that this pressure increase w...

Skin irritation is a common phenomenon that becomes a real concern when caused by the use of medical devices. Because the materials used for the design of these devices are usually carefully selected for chemical compatibility with the skin, it is reasonable to assume that the irritations result from the mechanical interaction between the devices a...

The skin is subject to daily mechanical stress when in contact with objects. Being able to make predictions about the skin's ability to withstand interactions with every day used products is therefore of great interest. Skin mechanical behaviour has already been widely studied. However, the current understanding of the through layer behaviour of s...

Low-back pain (LBP) is a widespread disease which can also be highly disabling, but physicians lack of basic understanding and diagnosis tools. During this study, we have designed and built a new wearable device capable of detecting features helpful in LBP follow-up while being non-invasive. The device has been carefully validated, and shows good m...

Objective: A numerical 3D model of the human trunk was developed to study the biomechanical effects of lumbar belts used to treat low back pain. Methods: This model was taken from trunk radiographies of a person and simplified so as to make a parametric study by varying morphological parameters of the patient, characteristic parameters of the lumba...

Elastic compression of the lower leg is the traditional preventive and curative treatment of venous insufficiency. After presenting the medical strategies related to compression therapies, this chapter develops current advances in clinics as well as in engineering and outline the more important knowledge arising from this review. Compression hosier...

The mechanical behavior of the foot is often studied through the movement of the segments composing it and not through the movement of each individual bone, preventing an accurate and unambiguous study of soft tissue strains and foot posture. In order to describe the internal behavior of the foot under static load, we present here an original metho...

Objective: A numerical 3D model of the human trunk was developed to study the biomechanical effects of lumbar belts used to treat low back pain.

Understanding stress-strain relationships in arteries is important for fundamental investigations in mechanobiology. Here we demonstrate the essential role of chemoelasticity in determining the mechanical properties of arterial tissues. Stepwise stress-relaxation uniaxial tensile tests were carried out on samples of porcine thoracic aortas immersed...

Understanding stress-strain relationships in arteries is important for fundamental investigations in mechanobiology. Here we demonstrate the essential role of chemoelasticity in determining the mechanical properties of arterial tissues. Stepwise stress-relaxation uniaxial tensile tests were carried out on samples of porcine thoracic aortas immersed...

Fabric-to-fabric friction is involved in the action mechanism of medical compression devices such as compression bandages or lumbar belts. To better understand the action of such devices, it is essential to characterize, in their use conditions (mainly pressure and stretch), the frictional properties of the fabrics they are composed of. A character...

file:///home/jerome/T%C3%A9l%C3%A9chargements/Biomechanical%20consequences%20of%20lumbar%20belt%20design%20for%20the%20therapeutic%20treatment%20of%20low%20back%20pain.pdf

Compression bandages are widely used in the management of venous and lymphatic disorders. They are sometimes used alone, often combined/ superimposed. In any case, their efficacy depends on the interface pressure applied either on the leg or on the arm. In order to identify the key parameters, which influence the interface pressure, this original...

Ascending thoracic aortic aneurysm (ATAA) ruptures are life threatening phenomena which occur in local weaker regions of the diseased aortic wall. As ATAAs are evolving pathologies, their growth represents a significant local remodeling and degradation of the microstructural architecture and thus their mechanical properties. To address the need for...

Lower back pain is a major public health problem. Despite claims that lumbar belts change spinal posture due to applied pressure on the trunk, no mechanical model has yet been published to prove this treatment. This paper describes a first model for belt design, based on the one hand on the mechanical properties of the fabrics and the belt geometry...

Supporting information. The ZIP file contains rough data corresponding to the tensile tests and body shape. All data are provided in CSV file format. (ZIP)

Objectifs Les dispositifs médicaux de compression (DMC) constituent le traitement de référence de l’insuffisance veineuse. Ces dispositifs sont basés sur des textiles tissés ou tricotés, chaussettes, bas ou bandes, et agissent sur les jambes par compression ou contention. Leur action mécanique doit être contrôlée, cependant aucune norme européenne...

Whereas industrial elastohydrodynamic (EHD) contacts are generally non-circular, most experimental observations are made on sphere-on-plane conjunctions. The circular case is indeed a specific elliptical case, and it was widely investigated. The differential colorimetric interferometry (DCI) technique was often used to perform precise film thicknes...

Optical coherence tomography (OCT) combined with digital volume correlation (DVC) is a suitable technique to investigate the biomechanical behavior of biological tissues at the microscale. However, to characterize the whole thickness of large human or porcine arteries, the use of osmotic tissue clearing agents, such as propylene glycol (PG), is una...

Objective: To develop a new method for the prediction of interface pressure applied by medical compression bandages. Methods: A finite element simulation of bandage application was designed, based on patient-specific leg geometries. For personalized interface pressure prediction, a model reduction approach was proposed, which included the parame...

In this study, the movement of climbing a step is decomposed in 4 EOS images. A patient-dependent 3D model of the knee is then created from MRI, and several numerical simulations are carried out according to the experimental boundary conditions (force and flexion angle), so as to ensure the global knee mechanical equilibrium. To validate this patie...

This chapter presents a quick and efficient approach to performing patient-specific finite-element (FE) predictions of the human calf response under elastic compression. The reconstruction of patient-specific material properties of soft tissues is based on two methodologies described extensively in two previous papers (. Frauziols et al., 2015, 201...

Objective The objective of this study was to investigate the pressure applied by superimposed bandages and to compare it with the pressure applied by single-component bandages. Methods Six different bandages, composed of one elastic bandage, one nonelastic bandage, or both, were applied in a spiral pattern on both legs of 25 patients at risk of ve...

A non-invasive method is proposed to identify in vivo the passive mechanical properties of deep soft tissues in the human leg. Force-displacement curves in response to a localized compression of the calf are measured with a custom made experimental set-up. The material parameters of a finite element model are then calibrated against the experimenta...

Tissue engineered skin usually consist of a multi-layered visco-elastic material composed of a fibrillar matrix and cells. The complete mechanical characterization of these tissues has not yet been accomplished. The purpose of this study was to develop a multiscale approach to perform this characterization in order to link the development process o...

Objective With cartilage physiopathology, knee stability and therefore the subsequent loadings on ligaments have a strong impact in the development of knee osteoarthritis. To understand this phenomenon, authors are proposing different knee models. Most of them are without any flexion, some have been introduced by controlling actively muscular group...

Objective Although it is only a part of their therapeutic effect, the mechanical effect of compression or contention medical devices (CCMD) is always claimed by the manufacturers. However, the mechanism between the pressure application zone and the targeted organ is complex. It involves a purely passive mechanical effect and mechanisms related to t...

Objective Compression bandages are commonly used in the treatment of some venous or lymphatic pathologies. The success of the treatment relies on the applied pressure, which depends on several parameters, especially the bandage properties but also patients’ morphology. A previous experimental study showed that considering only patient's morphology...

Optical full-field methods enable non-contact measurements insensitive to electromagnetic radiation as well as full-field measurements. Optical full-field methods have led to the development of an original practice of experimentation in solid and structural mechanics known as photomechanics. This chapter discusses four common methods which includes...

This concluding chapter of the book illustrates a mechanical test involves hypotheses, implementation techniques and instrumentations. An industrial laboratory has developed a torque meter internally. It is made up of two disks, one mounted on the machine frame, the other supporting the items to be tested. The subject of interest is a composite bea...

This chapter presents a measurement method that enables a minimum number of tests to obtain a maximum amount of information. It discusses the obtained quality of the information, depending on the quality of the descriptive model and also by comparing the results with an experimental dispersion. These two approaches are generally known as design exp...

The mechanical tests performed in solid and structural mechanics have different objectives, depending on the level of knowledge sought through these tests: primarily, the characterization tests allow understanding of undefined mechanisms. This chapter outlines the logic leading to the selection of a test and the validity of the test selected. Refer...

The conventional sensors used in solid and structural mechanics essentially allow the measurement of displacement, strain, force, and acceleration. The measurements of displacement, strain, force, and acceleration can be obtained using various different technologies. This chapter discusses a few technologies that are very commonly used. The most co...

Depuis la caractérisation des matériaux jusqu’aux tests de durée de vie, l’expérimentation des solides et des structures est présente à toutes les étapes de la conception de dispositifs mécaniques. Parfois, seul un modèle expérimental peut apporter les éléments de compréhension nécessaires, la physique étudiée étant trop complexe pour un modèle num...

The Robert Jones bandage (RJ) is a widely used bandage among veterinary surgeons to maintain physiological position of the limbs. It is a 3-layer composite bandage, which realization involves the use of several types of bands in a specific arrangement to give the bandage all its properties. Its proper making is difficult and requires experience, as...

Compression therapy with stockings or bandages is the most common treatment for venous or lymphatic disorders. The objective of this study was to investigate the influence of bandage mechanical properties, application technique and subject morphology on the interface pressure, which is the key of this treatment. Bandage stretch and interface pressu...

Background: The knee joint is vulnerable to various injuries and degenerative conditions, potentially leading to functional instability. Usual treatments involve knee orthoses to support the joint. However, the level of mechanical action of these devices remains controversial despite high prescription and demand. Methods: The mechanical ability...

Goal: In the present study, the biomechanical response of soft tissues from the fascia cruris to the skin is studied in the human leg under elastic compression. Methods: The distribution of elastic moduli in these tissues is measured for a volunteer at inactive and active muscle states using transient ultrasound elastography (TUSE). After regist...

The purpose of this study is to evaluate the possible use of four "FSA" thin and flexible resistive pressure mapping systems, designed by Vista Medical (Winnipeg, Manitoba, Canada), for the measurement of interface pressure exerted by lumbar belts onto the trunk. These sensors were originally designed for the measurement of low pressure applied by...

Knee orthotic devices are widely proposed by physicians and medical practitioners for preventive or therapeutic objectives in relation with their effects, usually known as to stabilize joint or restrict ranges of motion. This study focuses on the understanding of force transfer mechanisms from the brace to the joint thanks to a Finite Element Model...

Compression of the lower leg by bandages is a common treatment for the advanced stages of some venous or lymphatic pathologies. The outcomes of this treatment directly result from the pressure generated onto the limb. Various bandage configurations are proposed by manufacturers: the study of these configurations requires the development of reliable...

Low back pain is a major public health problem in European Countries. In France, about 50% of population is suffering of this pathology every year [Fassier, 2011]. Because of health care cost and sick leave [Fassier, 2011], [Leclerc, 2009], low back pain as both societal and economic adverse consequences. Concerning medical devices, such as lumbar...

Knee orthotic devices are commonly prescribed by physicians and medical practitioners for preventive or therapeutic purposes with the aim of supporting, aligning or immobilising the joint. However, the evaluation of these devices relies on few biomechanical studies or therapeutic trials and the level of their mechanical actions remain unclear. The...

Fabric-based knee braces are widely used as orthotic devices to support and align the joint. Despite significant prescription, compliance with the treatment is often negatively affected by discomfort issues, in particular brace slippage and migration. Full-field measurements associated with digital image correlation were performed on 11 subjects to...

The paper presents an alternative way to classical stereocorrelation. First, 2D image processing of random patterns is described. Sub-pixel displacements are determined using phase analysis. Then distortion evaluation is presented. The distortion is identified without any assumption on the lens model because of the use of a grid technique approach....

Optical full-field techniques have a great importance in modern experimental mechanics. Even if they are reasonably spread among the university laboratories, their diffusion in industrial companies remains very narrow for several reasons, especially a lack of metrological performance assessment. A full-field measurement can be characterized by its...

Knee orthotic devices are commonly prescribed by physicians and medical practitioners for preventive or therapeutic purposes on account of their claimed effect: joint stabilisation and proprioceptive input. However, the force transfer mechanisms of these devices and their level of action remain controversial. The objectives of this work are to char...

In France, 50% of the population per year is suffering from low back pain. Lumbar belt are frequently proposed as a part of the treatment of this pathology. However mechanical ways of working of this medical device is not clearly understood, but abdominal pressure is often related. So an optical method was developed in this study to measure strain...

Human skin is one of the most important organ of the body. The assessment and knowledge of its properties are very useful for clinical or cosmetic research. Many techniques are used to measure the mechanical properties of this organ, like suction, indentation, torsion or tension tests. The aim of this paper is to present a new device based on tensi...

A complete uncertainty analysis on a given fringe projection set-up has been performed using Monte-Carlo approach. In particular the calibration procedure is taken into account. Two applications are given: at a macroscopic scale, phase noise is predominant whilst at microscopic scale, both phase noise and calibration errors are important. Finally,...

This paper presents research on the densification and thermal gradient evolution of pure and magnesia-doped alumina during microwave sintering in a multimode cavity. Dimensional changes of pellets are registered by a contactless dilatometer that is part of a specifically prepared experimental system. Measurements of dimensional changes are compared...

The ply elastic constants needed for classical lamination theory analysis of multi-directional laminates may differ from those obtained from unidirectional laminates because of three dimensional effects. In addition, the unidirectional laminates may not be available for testing. In such cases, full-field displacement measurements offer the potentia...

Introduction Principle Surface Encoding Moiré Phase Detection Sensitivity to Out-of-Plane Displacements Grid Defects Large Deformation/Large Strain Fringe Projection Deflectometry Examples Conclusion Bibliography

Liquid resin infusion (LRI) processes are promising manufacturing routes to produce large, thick, or complex structural parts. They are based on the resin flow induced, across its thickness, by a pressure applied onto a preform/resin stacking. However, both thickness and fiber volume fraction of the final piece are not well controlled since they re...